You shall not commit adultery. [Ex 20:14; Deut 5:18]
You have heard that it was said, "You shall not commit adultery." But I say to you that every one who looks at a woman lustfully has already committed adultery with her in his heart. [Mt 5:27-28]
2331 "God is love and in himself he lives a mystery of personal loving communion. Creating the human race in his own image . . .. God inscribed in the humanity of man and woman the vocation, and thus the capacity and responsibility, of love and communion." [FC 11] 
"God created man in his own image... male and female he created them"; [Gen 1:27] He blessed them and said, "Be fruitful and multiply"; [Gen 1:28] "When God created man, he made him in the likeness of God. Male and female he created them, and he blessed them and named them Man when they were created." [Gen 5:1-2]
2332 Sexuality affects all aspects of the human person in the unity of his body and soul. It especially concerns affectivity, the capacity to love and to procreate, and in a more general way the aptitude for forming bonds of communion with others. 
2333 Everyone, man and woman, should acknowledge and accept his sexual identity. Physical, moral, and spiritual difference and complementarity are oriented toward the goods of marriage and the flourishing of family life. The harmony of the couple and of society depends in part on the way in which the complementarity, needs, and mutual support between the sexes are lived out. 
2334 "In creating men 'male and female,' God gives man and woman an equal personal dignity." [FC 22; Cf. GS 49 # 2] "Man is a person, man and woman equally so, since both were created in the image and likeness of the personal God." [MD 6] 
2335 Each of the two sexes is an image of the power and tenderness of God, with equal dignity though in a different way. The union of man and woman in marriage is a way of imitating in the flesh the Creator's generosity and fecundity: "Therefore a man leaves his father and his mother and cleaves to his wife, and they become one flesh." [Gen 2:24] All human generations proceed from this union. [Cf. Gen 4:1-2, 25-26; 5:1] 
2336 Jesus came to restore creation to the purity of its origins. In the Sermon on the Mount, he interprets God's plan strictly: "You have heard that it was said, 'You shall not commit adultery.' But I say to you that every one who looks at a woman lustfully has already committed adultery with her in his heart." [Mt 5:27-28] What God has joined together, let not man put asunder. [Cf. Mt 19:6] 
The tradition of the Church has understood the sixth commandment as encompassing the whole of human sexuality.
2337 Chastity means the successful integration of sexuality within the person and thus the inner unity of man in his bodily and spiritual being. Sexuality, in which man's belonging to the bodily and biological world is expressed, becomes personal and truly human when it is integrated into the relationship of one person to another, in the complete and lifelong mutual gift of a man and a woman. [2520, 
The virtue of chastity therefore involves the integrity of the person and the integrality of the gift.
2338 The chaste person maintains the integrity of the powers of life and love placed in him. This integrity ensures the unity of the person; it is opposed to any behavior that would impair it. It tolerates neither a double life nor duplicity in speech. [Cf. Mt 5:37]
2339 Chastity includes an apprenticeship in self-mastery which is a training in human freedom. The alternative is clear: either man governs his passions and finds peace, or he lets himself be dominated by them and becomes unhappy. [Cf. Sir 1:22] "Man's dignity therefore requires him to act out of conscious and free choice, as moved and drawn in a personal way from within, and not by blind impulses in himself or by mere external constraint. Man gains such dignity when, ridding himself of all slavery to the passions, he presses forward to his goal by freely choosing what is good and, by his diligence and skill, effectively secures for himself the means suited to this end." [GS 17] 
2340 Whoever wants to remain faithful to his baptismal promises and resist temptations will want to adopt the means for doing so: self-knowledge, practice of an ascesis adapted to the situations that confront him, obedience to God's commandments, exercise of the moral virtues, and fidelity to prayer. "Indeed it is through chastity that we are gathered together and led back to the unity from which we were fragmented into multiplicity." [St. Augustine, Conf. 10, 29, 40: PL 32, 796] 
2341 The virtue of chastity comes under the cardinal virtue of temperance, which seeks to permeate the passions and appetites of the senses with reason. 
2342 Self-mastery is a long and exacting work. One can never consider it acquired once and for all. It presupposes renewed effort at all stages of life. [Cf. Titus 2:1-6] The effort required can be more intense in certain periods, such as when the personality is being formed during childhood and adolescence. 
2343 Chastity has laws of growth which progress through stages marked by imperfection and too often by sin. "Man... day by day builds himself up through his many free decisions; and so he knows, loves, and accomplishes moral good by stages of growth." [FC 34] 
2344 Chastity represents an eminently personal task; it also involves a cultural effort, for there is "an interdependence between personal betterment and the improvement of society." [GS 25 # 1] Chastity presupposes respect for the rights of the person, in particular the right to receive information and an education that respect the moral and spiritual dimensions of human life. 
2345 Chastity is a moral virtue. It is also a gift from God, a grace, a fruit of spiritual effort. [Cf. Gal 5:22] The Holy Spirit enables one whom the water of Baptism has regenerated to imitate the purity of Christ. [Cf. 1 Jn 3:3] 
2346 Charity is the form of all the virtues. Under its influence, chastity appears as a school of the gift of the person. Self-mastery is ordered to the gift of self. Chastity leads him who practices it to become a witness to his neighbor of God's fidelity and loving kindness. [1827, 210]
2347 The virtue of chastity blossoms in friendship. It shows the disciple how to follow and imitate him who has chosen us as his friends, [Cf. Jn 15:15] who has given himself totally to us and allows us to participate in his divine estate. Chastity is a promise of immortality. 
Chastity is expressed notably in friendship with one's neighbor. Whether it develops between persons of the same or opposite sex, friendship represents a great good for all. It leads to spiritual communion.
2348 All the baptized are called to chastity. The Christian has "put on Christ," [Gal 3:27] the model for all chastity. All Christ's faithful are called to lead a chaste life in keeping with their particular states of life. At the moment of his Baptism, the Christian is pledged to lead his affective life in chastity.
2349 "People should cultivate [chastity] in the way that is suited to their state of life. Some profess virginity or consecrated celibacy which enables them to give themselves to God alone with an undivided heart in a remarkable manner. Others live in the way prescribed for all by the moral law, whether they are married or single." [CDF, Persona humana 11] Married people are called to live conjugal chastity; others practice chastity in continence: 
There are three forms of the virtue of chastity: the first is that of spouses, the second that of widows, and the third that of virgins. We do not praise any one of them to the exclusion of the others.... This is what makes for the richness of the discipline of the Church. [St. Ambrose, De viduis 4, 23: PL 16, 255A]
2350 Those who are engaged to marry are called to live chastity in continence. They should see in this time of testing a discovery of mutual respect, an apprenticeship in fidelity, and the hope of receiving one another from God. They should reserve for marriage the expressions of affection that belong to married love. They will help each other grow in chastity. 
2351 Lust is disordered desire for or inordinate enjoyment of sexual pleasure. Sexual pleasure is morally disordered when sought for itself, isolated from its procreative and unitive purposes. 
2352 By masturbation is to be understood the deliberate stimulation of the genital organs in order to derive sexual pleasure. "Both the Magisterium of the Church, in the course of a constant tradition, and the moral sense of the faithful have been in no doubt and have firmly maintained that masturbation is an intrinsically and gravely disordered action." [CDF, Persona humana 9] "The deliberate use of the sexual faculty, for whatever reason, outside of marriage is essentially contrary to its purpose." For here sexual pleasure is sought outside of "the sexual relationship which is demanded by the moral order and in which the total meaning of mutual self-giving and human procreation in the context of true love is achieved." [CDF, Persona humana 9]
To form an equitable judgment about the subjects' moral responsibility and to guide pastoral action, one must take into account the affective immaturity, force of acquired habit, conditions of anxiety, or other psychological or social factors that can lessen, if not even reduce to a minimum, moral culpability. 
2353 Fornication is carnal union between an unmarried man and an unmarried woman. It is gravely contrary to the dignity of persons and of human sexuality which is naturally ordered to the good of spouses and the generation and education of children. Moreover, it is a grave scandal when there is corruption of the young.
2354 Pornography consists in removing real or simulated sexual acts from the intimacy of the partners, in order to display them deliberately to third parties. It offends against chastity because it perverts the conjugal act, the intimate giving of spouses to each other. It does grave injury to the dignity of its participants (actors, vendors, the public), since each one becomes an object of base pleasure and illicit profit for others. It immerses all who are involved in the illusion of a fantasy world. It is a grave offense. Civil authorities should prevent the production and distribution of pornographic materials. 
2355 Prostitution does injury to the dignity of the person who engages in it, reducing the person to an instrument of sexual pleasure. The one who pays sins gravely against himself: he violates the chastity to which his Baptism pledged him and defiles his body, the temple of the Holy Spirit. [Cf. 1 Cor 6:15-20] Prostitution is a social scourge. It usually involves women, but also men, children, and adolescents (The latter two cases involve the added sin of scandal.). While it is always gravely sinful to engage in prostitution, the imputability of the offense can be attenuated by destitution, blackmail, or social pressure. 
2356 Rape is the forcible violation of the sexual intimacy of another person. It does injury to justice and charity. Rape deeply wounds the respect, freedom, and physical and moral integrity to which every person has a right. It causes grave damage that can mark the victim for life. It is always an intrinsically evil act. Graver still is the rape of children committed by parents (incest) or those responsible for the education of the children entrusted to them. [2297, 1756, 2388]
2357 Homosexuality refers to relations between men or between women who experience an exclusive or predominant sexual attraction toward persons of the same sex. It has taken a great variety of forms through the centuries and in different cultures. Its psychological genesis remains largely unexplained. Basing itself on Sacred Scripture, which presents homosexual acts as acts of grave depravity, [Cf. Gen 191-29; Rom 124-27; 1 Cor 6:10; 1 Tim 1:10] tradition has always declared that "homosexual acts are intrinsically disordered." [CDF, Persona humana 8] They are contrary to the natural law. They close the sexual act to the gift of life. They do not proceed from a genuine affective and sexual complementarity. Under no circumstances can they be approved. 
2358 The number of men and women who have deep-seated homosexual tendencies is not negligible. This inclination, which is objectively disordered, constitutes for most of them a trial. They must be accepted with respect, compassion, and sensitivity. Every sign of unjust discrimination in their regard should be avoided. These persons are called to fulfill God's will in their lives and, if they are Christians, to unite to the sacrifice of the Lord's Cross the difficulties they may encounter from their condition.
2359 Homosexual persons are called to chastity. By the virtues of self-mastery that teach them inner freedom, at times by the support of disinterested friendship, by prayer and sacramental grace, they can and should gradually and resolutely approach Christian perfection. 
2360 Sexuality is ordered to the conjugal love of man and woman. In marriage the physical intimacy of the spouses becomes a sign and pledge of spiritual communion. Marriage bonds between baptized persons are sanctified by the sacrament. 
2361 "Sexuality, by means of which man and woman give themselves to one another through the acts which are proper and exclusive to spouses, is not something simply biological, but concerns the innermost being of the human person as such. It is realized in a truly human way only if it is an integral part of the love by which a man and woman commit themselves totally to one another until death." [FC 11] [1643, 2332]
Tobias got out of bed and said to Sarah, "Sister, get up, and let us pray and implore our Lord that he grant us mercy and safety." So she got up, and they began to pray and implore that they might be kept safe. Tobias began by saying, "Blessed are you, O God of our fathers.... You made Adam, and for him you made his wife Eve as a helper and support. From the two of them the race of mankind has sprung. You said, 'It is not good that the man should be alone; let us make a helper for him like himself.' I now am taking this kinswoman of mine, not because of lust, but with sincerity. Grant that she and I may find mercy and that we may grow old together." And they both said, "Amen, Amen." Then they went to sleep for the night. [Tob 8:4-9] 
2362 "The acts in marriage by which the intimate and chaste union of the spouses takes place are noble and honorable; the truly human performance of these acts fosters the self-giving they signify and enriches the spouses in joy and gratitude." [GS 49 # 2] Sexuality is a source of joy and pleasure:
The Creator himself... established that in the [generative] function, spouses should experience pleasure and enjoyment of body and spirit. Therefore, the spouses do nothing evil in seeking this pleasure and enjoyment. They accept what the Creator has intended for them. At the same time, spouses should know how to keep themselves within the limits of just moderation. [Pius XII, Discourse, October 29,1951]
2363 The spouses' union achieves the twofold end of marriage: the good of the spouses themselves and the transmission of life. These two meanings or values of marriage cannot be separated without altering the couple's spiritual life and compromising the goods of marriage and the future of the family.
The conjugal love of man and woman thus stands under the twofold obligation of fidelity and fecundity.
2364 The married couple forms "the intimate partnership of life and love established by the Creator and governed by his laws; it is rooted in the conjugal covenant, that is, in their irrevocable personal consent." [GS 48 # 1] Both give themselves definitively and totally to one another. They are no longer two; from now on they form one flesh. The covenant they freely contracted imposes on the spouses the obligation to preserve it as unique and indissoluble. [Cf. CIC, can. 1056] "What therefore God has joined together, let not man put asunder." [Mk 109; cf. Mt 19:1-12; 1 Cor 7: 10-11] [1603, 1615]
2365 Fidelity expresses constancy in keeping one's given word. God is faithful. The Sacrament of Matrimony enables man and woman to enter into Christ's fidelity for his Church. Through conjugal chastity, they bear witness to this mystery before the world. 
St. John Chrysostom suggests that young husbands should say to their wives: I have taken you in my arms, and I love you, and I prefer you to my life itself. For the present life is nothing, and my most ardent dream is to spend it with you in such a way that we may be assured of not being separated in the life reserved for us.... I place your love above all things, and nothing would be more bitter or painful to me than to be of a different mind than you. [St. John Chrysostom, Hom. in Eph. 20, 8: PG 62, 146-147]
2366 Fecundity is a gift, an end of marriage, for conjugal love naturally tends to be fruitful. A child does not come from outside as something added on to the mutual love of the spouses, but springs from the very heart of that mutual giving, as its fruit and fulfillment. So the Church, which "is on the side of life," teaches that "it is necessary that each and every marriage act remain ordered per se to the procreation of human life." [HV 11] "This particular doctrine, expounded on numerous occasions by the Magisterium, is based on the inseparable connection, established by God, which man on his own initiative may not break, between the unitive significance and the procreative significance which are both inherent to the marriage act." [HV 12; cf. Pius XI, encyclical, Casti connubii]
2367 Called to give life, spouses share in the creative power and fatherhood of God. [Cf. Eph 3:14; Mt 23:9] "Married couples should regard it as their proper mission to transmit human life and to educate their children; they should realize that they are thereby cooperating with the love of God the Creator and are, in a certain sense, its interpreters. They will fulfill this duty with a sense of human and Christian responsibility." [GS 50 # 2] 
2368 A particular aspect of this responsibility concerns the regulation of procreation. For just reasons, spouses may wish to space the births of their children. It is their duty to make certain that their desire is not motivated by selfishness but is in conformity with the generosity appropriate to responsible parenthood. Moreover, they should conform their behavior to the objective criteria of morality:
When it is a question of harmonizing married love with the responsible transmission of life, the morality of the behavior does not depend on sincere intention and evaluation of motives alone; but it must be determined by objective criteria, criteria drawn from the nature of the person and his acts criteria that respect the total meaning of mutual self-giving and human procreation in the context of true love; this is possible only if the virtue of married chastity is practiced with sincerity of heart. [GS 51 # 3]
2369 "By safeguarding both these essential aspects, the unitive and the procreative, the conjugal act preserves in its fullness the sense of true mutual love and its orientation toward man's exalted vocation to parenthood." [Cf. HV 12]
2370 Periodic continence, that is, the methods of birth regulation based on self- observation and the use of infertile periods, is in conformity with the objective criteria of morality. [HV 16] These methods respect the bodies of the spouses, encourage tenderness between them, and favor the education of an authentic freedom. In contrast, "every action which, whether in anticipation of the conjugal act, or in its accomplishment, or in the development of its natural consequences, proposes, whether as an end or as a means, to render procreation impossible" is intrinsically evil: [HV 14]
Thus the innate language that expresses the total reciprocal self-giving of husband and wife is overlaid, through contraception, by an objectively contradictory language, namely, that of not giving oneself totally to the other. This leads not only to a positive refusal to be open to life but also to a falsification of the inner truth of conjugal love, which is called upon to give itself in personal totality.... The difference, both anthropological and moral, between contraception and recourse to the rhythm of the cycle... involves in the final analysis two irreconcilable concepts of the human person and of human sexuality. [FC 32]
2371 "Let all be convinced that human life and the duty of transmitting it are not limited by the horizons of this life only: their true evaluation and full significance can be understood only in reference to man's eternal destiny." [GS 51 # 4] 
2372 The state has a responsibility for its citizens' well-being. In this capacity it is legitimate for it to intervene to orient the demography of the population. This can be done by means of objective and respectful information, but certainly not by authoritarian, coercive measures. The state may not legitimately usurp the initiative of spouses, who have the primary responsibility for the procreation and education of their children. [Cf. HV 23; PP 37] It is not authorized to intervene in this area with means contrary to the moral law. 
2373 Sacred Scripture and the Church's traditional practice see in large families a sign of God's blessing and the parents' generosity. [Cf. GS 50 # 2]
2374 Couples who discover that they are sterile suffer greatly. "What will you give me," asks Abraham of God, "for I continue childless?" [Gen 15:2] And Rachel cries to her husband Jacob, "Give me children, or I shall die!" [Gen 30:1] 
2375 Research aimed at reducing human sterility is to be encouraged, on condition that it is placed "at the service of the human person, of his inalienable rights, and his true and integral good according to the design and will of God." [CDF, Donum vitae intro., 2] 
2376 Techniques that entail the dissociation of husband and wife, by the intrusion of a person other than the couple (donation of sperm or ovum, surrogate uterus), are gravely immoral. These techniques (heterologous artificial insemination and fertilization) infringe the child's right to be born of a father and mother known to him and bound to each other by marriage. They betray the spouses' "right to become a father and a mother only through each other." [CDF, Donum vitae II, 1]
2377 Techniques involving only the married couple (homologous artificial insemination and fertilization) are perhaps less reprehensible, yet remain morally unacceptable. They dissociate the sexual act from the procreative act. The act which brings the child into existence is no longer an act by which two persons give themselves to one another, but one that "entrusts the life and identity of the embryo into the power of doctors and biologists and establishes the domination of technology over the origin and destiny of the human person. Such a relationship of domination is in itself contrary to the dignity and equality that must be common to parents and children." [CDF, Donum vitae II, 5] "Under the moral aspect procreation is deprived of its proper perfection when it is not willed as the fruit of the conjugal act, that is to say, of the specific act of the spouses' union .... Only respect for the link between the meanings of the conjugal act and respect for the unity of the human being make possible procreation in conformity with the dignity of the person." [CDF, Donum vitae II, 4]
2378 A child is not something owed to one, but is a gift. The "supreme gift of marriage" is a human person. A child may not be considered a piece of property, an idea to which an alleged "right to a child" would lead. In this area, only the child possesses genuine rights: the right "to be the fruit of the specific act of the conjugal love of his parents," and "the right to be respected as a person from the moment of his conception." [CDF, Donum vitae II, 8]
2379 The Gospel shows that physical sterility is not an absolute evil. Spouses who still suffer from infertility after exhausting legitimate medical procedures should unite themselves with the Lord's Cross, the source of all spiritual fecundity. They can give expression to their generosity by adopting abandoned children or performing demanding services for others.
2380 Adultery refers to marital infidelity. When two partners, of whom at least one is married to another party, have sexual relations - even transient ones - they commit adultery. Christ condemns even adultery of mere desire. [Cf. Mt 5:27-28] The sixth commandment and the New Testament forbid adultery absolutely. [Cf. Mt 5:32; 19:6; Mk 10:11; 1 Cor 6:9-10] The prophets denounce the gravity of adultery; they see it as an image of the sin of idolatry. [Cf. Hos 2:7; Jer 5:7; 13:27] 
2381 Adultery is an injustice. He who commits adultery fails in his commitment. He does injury to the sign of the covenant which the marriage bond is, transgresses the rights of the other spouse, and undermines the institution of marriage by breaking the contract on which it is based. He compromises the good of human generation and the welfare of children who need their parents' stable union. 
2382 The Lord Jesus insisted on the original intention of the Creator who willed that marriage be indissoluble. [Cf. Mt 5:31-32; 19:3-9; Mk 10 9; Lk 16:18; 1 Cor 7:10-ll] He abrogates the accommodations that had slipped into the old Law. [Cf. Mt 19:7-9] 
Between the baptized, "a ratified and consummated marriage cannot be dissolved by any human power or for any reason other than death." [CIC, can. 1141]
2383 The separation of spouses while maintaining the marriage bond can be legitimate in certain cases provided for by canon law. [Cf. CIC, cann. 1151-1155] 
If civil divorce remains the only possible way of ensuring certain legal rights, the care of the children, or the protection of inheritance, it can be tolerated and does not constitute a moral offense.
2384 Divorce is a grave offense against the natural law. It claims to break the contract, to which the spouses freely consented, to live with each other till death. Divorce does injury to the covenant of salvation, of which sacramental marriage is the sign. Contracting a new union, even if it is recognized by civil law, adds to the gravity of the rupture: the remarried spouse is then in a situation of public and permanent adultery: 
If a husband, separated from his wife, approaches another woman, he is an adulterer because he makes that woman commit adultery, and the woman who lives with him is an adulteress, because she has drawn another's husband to herself. [St. Basil, Moralia 73, 1: PG 31, 849-852]
2385 Divorce is immoral also because it introduces disorder into the family and into society. This disorder brings grave harm to the deserted spouse, to children traumatized by the separation of their parents and often torn between them, and because of its contagious effect which makes it truly a plague on society.
2386 It can happen that one of the spouses is the innocent victim of a divorce decreed by civil law; this spouse therefore has not contravened the moral law. There is a considerable difference between a spouse who has sincerely tried to be faithful to the sacrament of marriage and is unjustly abandoned, and one who through his own grave fault destroys a canonically valid marriage. [Cf. FC 84] 
2387 The predicament of a man who, desiring to convert to the Gospel, is obliged to repudiate one or more wives with whom he has shared years of conjugal life, is understandable. However polygamy is not in accord with the moral law." [Conjugal] communion is radically contradicted by polygamy; this, in fact, directly negates the plan of God which was revealed from the beginning, because it is contrary to the equal personal dignity of men and women who in matrimony give themselves with a love that is total and therefore unique and exclusive." [FC 19; cf. GS 47 # 2] The Christian who has previously lived in polygamy has a grave duty in justice to honor the obligations contracted in regard to his former wives and his children. 
2388 Incest designates intimate relations between relatives or in-laws within a degree that prohibits marriage between them. [Cf. Lev 18:7-20] St. Paul stigmatizes this especially grave offense: "It is actually reported that there is immorality among you... for a man is living with his father's wife.... In the name of the Lord Jesus ... you are to deliver this man to Satan for the destruction of the flesh...." [1 Cor 5:1, 4-5] Incest corrupts family relationships and marks a regression toward animality. [2356, 2207]
2389 Connected to incest is any sexual abuse perpetrated by adults on children or adolescents entrusted to their care. The offense is compounded by the scandalous harm done to the physical and moral integrity of the young, who will remain scarred by it all their lives; and the violation of responsibility for their upbringing. 
2390 In a so-called free union, a man and a woman refuse to give juridical and public form to a liaison involving sexual intimacy. 
The expression "free union" is fallacious: what can "union" mean when the partners make no commitment to one another, each exhibiting a lack of trust in the other, in himself, or in the future?
The expression covers a number of different situations: concubinage, rejection of marriage as such, or inability to make long-term commitments. [Cf. FC 81] All these situations offend against the dignity of marriage; they destroy the very idea of the family; they weaken the sense of fidelity. They are contrary to the moral law. The sexual act must take place exclusively within marriage. Outside of marriage it always constitutes a grave sin and excludes one from sacramental communion. [2353, 1385]
2391 Some today claim a "right to a trial marriage" where there is an intention of getting married later. However firm the purpose of those who engage in premature sexual relations may be, "the fact is that such liaisons can scarcely ensure mutual sincerity and fidelity in a relationship between a man and a woman, nor, especially, can they protect it from inconstancy of desires or whim." [CDF, Persona humana 7] Carnal union is morally legitimate only when a definitive community of life between a man and woman has been established. Human love does not tolerate "trial marriages." It demands a total and definitive gift of persons to one another. [Cf. FC 80] 
2392 "Love is the fundamental and innate vocation of every human being" (FC 11).
2393 By creating the human being man and woman, God gives personal dignity equally to the one and the other. Each of them, man and woman, should acknowledge and accept his sexual identity.
2394 Christ is the model of chastity. Every baptized person is called to lead a chaste life, each according to his particular state of life.
2395 Chastity means the integration of sexuality within the person. It includes an apprenticeship in self-mastery.
2396 Among the sins gravely contrary to chastity are masturbation, fornication, pornography, and homosexual practices.
2397 The covenant which spouses have freely entered into entails faithful love. It imposes on them the obligation to keep their marriage indissoluble.
2398 Fecundity is a good, a gift and an end of marriage. By giving life, spouses participate in God's fatherhood.
2399 The regulation of births represents one of the aspects of responsible fatherhood and motherhood. Legitimate intentions on the part of the spouses do not justify recourse to morally unacceptable means (for example, direct sterilization or contraception).
2400 Adultery, divorce, polygamy, and free union are grave offenses against the dignity of marriage.
2401 The seventh commandment forbids unjustly taking or keeping the goods of one's neighbor and wronging him in any way with respect to his goods. It commands justice and charity in the care of earthly goods and the fruits of men's labor. For the sake of the common good, it requires respect for the universal destination of goods and respect for the right to private property. Christian life strives to order this world's goods to God and to fraternal charity. [1807, 952]
You shall not steal. [EX 20:15; Deut 5:19; Mt 19:18]
2402 In the beginning God entrusted the earth and its resources to the common stewardship of mankind to take care of them, master them by labor, and enjoy their fruits. [Cf. Gen 1:26-29] The goods of creation are destined for the whole human race. However, the earth is divided up among men to assure the security of their lives, endangered by poverty and threatened by violence. The appropriation of property is legitimate for guaranteeing the freedom and dignity of persons and for helping each of them to meet his basic needs and the needs of those in his charge. It should allow for a natural solidarity to develop between men. [226, 1939]
2403 The right to private property, acquired or received in a just way, does not do away with the original gift of the earth to the whole of mankind. The universal destination of goods remains primordial, even if the promotion of the common good requires respect for the right to private property and its exercise.
2404 "In his use of things man should regard the external goods he legitimately owns not merely as exclusive to himself but common to others also, in the sense that they can benefit others as well as himself." [GS 69 # 1] The ownership of any property makes its holder a steward of Providence, with the task of making it fruitful and communicating its benefits to others, first of all his family. 
2405 Goods of production - material or immaterial - such as land, factories, practical or artistic skills, oblige their possessors to employ them in ways that will benefit the greatest number. Those who hold goods for use and consumption should use them with moderation, reserving the better part for guests, for the sick and the poor.
2406 Political authority has the right and duty to regulate the legitimate exercise of the right to ownership for the sake of the common good. [Cf. GS 71 # 4; SRS 42; CA 40; 48] 
2407 In economic matters, respect for human dignity requires the practice of the virtue of temperance, so as to moderate attachment to this world's goods; the practice of the virtue of justice, to preserve our neighbor's rights and render him what is his due; and the practice of solidarity, in accordance with the golden rule and in keeping with the generosity of the Lord, who "though he was rich, yet for your sake... became poor so that by his poverty, you might become rich." [2 Cor 8:9] [1809, 1807, 1939]
2408 The seventh commandment forbids theft, that is, usurping another's property against the reasonable will of the owner. There is no theft if consent can be presumed or if refusal is contrary to reason and the universal destination of goods. This is the case in obvious and urgent necessity when the only way to provide for immediate, essential needs (food, shelter, clothing...) is to put at one's disposal and use the property of others. [Cf. GS 69 # 1]
2409 Even if it does not contradict the provisions of civil law, any form of unjustly taking and keeping the property of others is against the seventh commandment: thus, deliberate retention of goods lent or of objects lost; business fraud; paying unjust wages; forcing up prices by taking advantage of the ignorance or hardship of another. [Cf. Deut 25:13-16; 24:14-15; Jas 5:4; Am 8:4-6] 
The following are also morally illicit: speculation in which one contrives to manipulate the price of goods artificially in order to gain an advantage to the detriment of others; corruption in which one influences the judgment of those who must make decisions according to law; appropriation and use for private purposes of the common goods of an enterprise; work poorly done; tax evasion; forgery of checks and invoices; excessive expenses and waste. Willfully damaging private or public property is contrary to the moral law and requires reparation.
2410 Promises must be kept and contracts strictly observed to the extent that the commitments made in them are morally just. A significant part of economic and social life depends on the honoring of contracts between physical or moral persons - commercial contracts of purchase or sale, rental or labor contracts. All contracts must be agreed to and executed in good faith. 
2411 Contracts are subject to commutative justice which regulates exchanges between persons and between institutions in accordance with a strict respect for their rights. Commutative justice obliges strictly; it requires safeguarding property rights, paying debts, and fulfilling obligations freely contracted. Without commutative justice, no other form of justice is possible. 
One distinguishes commutative justice from legal justice which concerns what the citizen owes in fairness to the community, and from distributive justice which regulates what the community owes its citizens in proportion to their contributions and needs.
2412 In virtue of commutative justice, reparation for injustice committed requires the restitution of stolen goods to their owner: 
Jesus blesses Zacchaeus for his pledge: "If I have defrauded anyone of anything, I restore it fourfold." [Lk 19:8] Those who, directly or indirectly, have taken possession of the goods of another, are obliged to make restitution of them, or to return the equivalent in kind or in money, if the goods have disappeared, as well as the profit or advantages their owner would have legitimately obtained from them. Likewise, all who in some manner have taken part in a theft or who have knowingly benefited from it - for example, those who ordered it, assisted in it, or received the stolen goods - are obliged to make restitution in proportion to their responsibility and to their share of what was stolen. 
2413 Games of chance (card games, etc.) or wagers are not in themselves contrary to justice. They become morally unacceptable when they deprive someone of what is necessary to provide for his needs and those of others. The passion for gambling risks becoming an enslavement. Unfair wagers and cheating at games constitute grave matter, unless the damage inflicted is so slight that the one who suffers it cannot reasonably consider it significant.
2414 The seventh commandment forbids acts or enterprises that for any reason - selfish or ideological, commercial, or totalitarian - lead to the enslavement of human beings, to their being bought, sold and exchanged like merchandise, in disregard for their personal dignity. It is a sin against the dignity of persons and their fundamental rights to reduce them by violence to their productive value or to a source of profit. St. Paul directed a Christian master to treat his Christian slave "no longer as a slave but more than a slave, as a beloved brother,... both in the flesh and in the Lord." [Philem 16] 
2415 The seventh commandment enjoins respect for the integrity of creation. Animals, like plants and inanimate beings, are by nature destined for the common good of past, present, and future humanity. [Cf. Gen 128-31] Use of the mineral, vegetable, and animal resources of the universe cannot be divorced from respect for moral imperatives. Man's dominion over inanimate and other living beings granted by the Creator is not absolute; it is limited by concern for the quality of life of his neighbor, including generations to come; it requires a religious respect for the integrity of creation. [Cf. CA 37-38] [226, 358, 373, 378]
2416 Animals are God's creatures. He surrounds them with his providential care. By their mere existence they bless him and give him glory. [Cf. Mt 6:26; Dan 3:79-81] Thus men owe them kindness. We should recall the gentleness with which saints like St. Francis of Assisi or St. Philip Neri treated animals. 
2417 God entrusted animals to the stewardship of those whom he created in his own image. [Cf. Gen 2:19-20; 9:1-4] Hence it is legitimate to use animals for food and clothing. They may be domesticated to help man in his work and leisure. Medical and scientific experimentation on animals is a morally acceptable practice if it remains within reasonable limits and contributes to caring for or saving human lives. 
2418 It is contrary to human dignity to cause animals to suffer or die needlessly. It is likewise unworthy to spend money on them that should as a priority go to the relief of human misery. One can love animals; one should not direct to them the affection due only to persons. 
2419 "Christian revelation... promotes deeper understanding of the laws of social living." [GS 23 # 1] The Church receives from the Gospel the full revelation of the truth about man. When she fulfills her mission of proclaiming the Gospel, she bears witness to man, in the name of Christ, to his dignity and his vocation to the communion of persons. She teaches him the demands of justice and peace in conformity with divine wisdom. [1960, 359]
2420 The Church makes a moral judgment about economic and social matters, "when the fundamental rights of the person or the salvation of souls requires it." [GS 76 # 5] In the moral order she bears a mission distinct from that of political authorities: the Church is concerned with the temporal aspects of the common good because they are ordered to the sovereign Good, our ultimate end. She strives to inspire right attitudes with respect to earthly goods and in socio-economic relationships. [2032, 2246]
2421 The social doctrine of the Church developed in the nineteenth century when the Gospel encountered modern industrial society with its new structures for the production of consumer goods, its new concept of society, the state and authority, and its new forms of labor and ownership. The development of the doctrine of the Church on economic and social matters attests the permanent value of the Church's teaching at the same time as it attests the true meaning of her Tradition, always living and active. [Cf. CA 3]
2422 The Church's social teaching comprises a body of doctrine, which is articulated as the Church interprets events in the course of history, with the assistance of the Holy Spirit, in the light of the whole of what has been revealed by Jesus Christ. [Cf. SRS 1; 41] This teaching can be more easily accepted by men of good will, the more the faithful let themselves be guided by it. 
2423 The Church's social teaching proposes principles for reflection; it provides criteria for judgment; it gives guidelines for action:
Any system in which social relationships are determined entirely by economic factors is contrary to the nature of the human person and his acts. [Cf. CA 24]
2424 A theory that makes profit the exclusive norm and ultimate end of economic activity is morally unacceptable. The disordered desire for money cannot but produce perverse effects. It is one of the causes of the many conflicts which disturb the social order. [Cf. GS 63 # 3; LE 7; 20; CA 35] 
A system that "subordinates the basic rights of individuals and of groups to the collective organization of production" is contrary to human dignity. [GS 65 # 2] Every practice that reduces persons to nothing more than a means of profit enslaves man, leads to idolizing money, and contributes to the spread of atheism. "You cannot serve God and mammon." [Mt 6:24; Lk 16:13]
2425 The Church has rejected the totalitarian and atheistic ideologies associated in modem times with "communism" or "socialism." She has likewise refused to accept, in the practice of "capitalism," individualism and the absolute primacy of the law of the marketplace over human labor. [Cf. CA 10; 13; 44] Regulating the economy solely by centralized planning perverts the basis of social bonds; regulating it solely by the law of the marketplace fails social justice, for "there are many human needs which cannot be satisfied by the market." [CA 34] Reasonable regulation of the marketplace and economic initiatives, in keeping with a just hierarchy of values and a view to the common good, is to be commended. [676, 1886]
2426 The development of economic activity and growth in production are meant to provide for the needs of human beings. Economic life is not meant solely to multiply goods produced and increase profit or power; it is ordered first of all to the service of persons, of the whole man, and of the entire human community. Economic activity, conducted according to its own proper methods, is to be exercised within the limits of the moral order, in keeping with social justice so as to correspond to God's plan for man. [Cf. GS 64] 
2427 Human work proceeds directly from persons created in the image of God and called to prolong the work of creation by subduing the earth, both with and for one another. [Cf. Gen 1:28; GS 34; CA 31] Hence work is a duty: "If any one will not work, let him not eat." [2 Thess 3:10; Cf. 1 Thess 4:11] Work honors the Creator's gifts and the talents received from him. It can also be redemptive. By enduring the hardship of work [Cf. Gen 3:14-19] in union with Jesus, the carpenter of Nazareth and the one crucified on Calvary, man collaborates in a certain fashion with the Son of God in his redemptive work. He shows himself to be a disciple of Christ by carrying the cross, daily, in the work he is called to accomplish. [Cf. LE 27] Work can be a means of sanctification and a way of animating earthly realities with the Spirit of Christ. [307, 378, 531]
2428 In work, the person exercises and fulfills in part the potential inscribed in his nature. The primordial value of labor stems from man himself, its author and its beneficiary. Work is for man, not man for work. [Cf. LE 6] [2834, 2185]
Everyone should be able to draw from work the means of providing for his life and that of his family, and of serving the human community.
2429 Everyone has the right of economic initiative; everyone should make legitimate use of his talents to contribute to the abundance that will benefit all and to harvest the just fruits of his labor. He should seek to observe regulations issued by legitimate authority for the sake of the common good. [Cf. CA 32; 34]
2430 Economic life brings into play different interests, often opposed to one another. This explains why the conflicts that characterize it arise. [Cf. LE 11] Efforts should be made to reduce these conflicts by negotiation that respects the rights and duties of each social partner: those responsible for business enterprises, representatives of wage- earners (for example, trade unions), and public authorities when appropriate.
2431 The responsibility of the state. "Economic activity, especially the activity of a market economy, cannot be conducted in an institutional, juridical, or political vacuum. On the contrary, it presupposes sure guarantees of individual freedom and private property, as well as a stable currency and efficient public services. Hence the principal task of the state is to guarantee this security, so that those who work and produce can enjoy the fruits of their labors and thus feel encouraged to work efficiently and honestly.... Another task of the state is that of overseeing and directing the exercise of human rights in the economic sector. However, primary responsibility in this area belongs not to the state but to individuals and to the various groups and associations which make up society." [CA 48] [1908, 1883]
2432 Those responsible for business enterprises are responsible to society for the economic and ecological effects of their operations. [Cf. CA 37] They have an obligation to consider the good of persons and not only the increase of profits. Profits are necessary, however. They make possible the investments that ensure the future of a business and they guarantee employment. 
2433 Access to employment and to professions must be open to all without unjust discrimination: men and women, healthy and disabled, natives and immigrants. [Cf. LE 19; 22-23] For its part society should, according to circumstances, help citizens find work and employment. [Cf. CA 48]
2434 A just wage is the legitimate fruit of work. To refuse or withhold it can be a grave injustice. [Cf. Lev 19:13; Deut 24:14-15; Jas 5:4] In determining fair pay both the needs and the contributions of each person must be taken into account. "Remuneration for work should guarantee man the opportunity to provide a dignified livelihood for himself and his family on the material, social, cultural and spiritual level, taking into account the role and the productivity of each, the state of the business, and the common good." [GS 67 # 2] Agreement between the parties is not sufficient to justify morally the amount to be received in wages. 
2435 Recourse to a strike is morally legitimate when it cannot be avoided, or at least when it is necessary to obtain a proportionate benefit. It becomes morally unacceptable when accompanied by violence, or when objectives are included that are not directly linked to working conditions or are contrary to the common good.
2436 It is unjust not to pay the social security contributions required by legitimate authority.
Unemployment almost always wounds its victim's dignity and threatens the equilibrium of his life. Besides the harm done to him personally, it entails many risks for his family. [Cf. LE 18]
2437 On the international level, inequality of resources and economic capability is such that it creates a real "gap" between nations. [Cf. SRS 14] On the one side there are those nations possessing and developing the means of growth and, on the other, those accumulating debts. 
2438 Various causes of a religious, political, economic, and financial nature today give "the social question a worldwide dimension." [SRS 9] There must be solidarity among nations which are already politically interdependent. It is even more essential when it is a question of dismantling the "perverse mechanisms" that impede the development of the less advanced countries. [Cf. SRS 17; 45] In place of abusive if not usurious financial systems, iniquitous commercial relations among nations, and the arms race, there must be substituted a common effort to mobilize resources toward objectives of moral, cultural, and economic development, "redefining the priorities and hierarchies of values." [CA 28; Cf. 35] [1911, 2315]
2439 Rich nations have a grave moral responsibility toward those which are unable to ensure the means of their development by themselves or have been prevented from doing so by tragic historical events. It is a duty in solidarity and charity; it is also an obligation in justice if the prosperity of the rich nations has come from resources that have not been paid for fairly.
2440 Direct aid is an appropriate response to immediate, extraordinary needs caused by natural catastrophes, epidemics, and the like. But it does not suffice to repair the grave damage resulting from destitution or to provide a lasting solution to a country's needs. It is also necessary to reform international economic and financial institutions so that they will better promote equitable relationships with less advanced countries. [Cf. SRS 16] The efforts of poor countries working for growth and liberation must be supported. [Cf. CA 26] This doctrine must be applied especially in the area of agricultural labor. Peasants, especially in the Third World, form the overwhelming majority of the poor.
2441 An increased sense of God and increased self-awareness are fundamental to any full development of human society. This development multiplies material goods and puts them at the service of the person and his freedom. It reduces dire poverty and economic exploitation. It makes for growth in respect for cultural identities and openness to the transcendent. [Cf. SRS 32; CA 51] 
2442 It is not the role of the Pastors of the Church to intervene directly in the political structuring and organization of social life. This task is part of the vocation of the lay faithful, acting on their own initiative with their fellow citizens. Social action can assume various concrete forms. It should always have the common good in view and be in conformity with the message of the Gospel and the teaching of the Church. It is the role of the laity "to animate temporal realities with Christian commitment, by which they show that they are witnesses and agents of peace and justice." [SRS 47 # 6; cf. 42] 
2443 God blesses those who come to the aid of the poor and rebukes those who turn away from them: "Give to him who begs from you, do not refuse him who would borrow from you"; "you received without pay, give without pay." [Mt 5:42; 10:8] It is by what they have done for the poor that Jesus Christ will recognize his chosen ones. [Cf. Mt 25:31-36] When "the poor have the good news preached to them," it is the sign of Christ's presence. [Mt 11:5; cf. Lk 4:18] [786, 525, 544, 853]
2444 "The Church's love for the poor... is a part of her constant tradition." This love is inspired by the Gospel of the Beatitudes, of the poverty of Jesus, and of his concern for the poor. [CA 57; cf. Lk 6:20-22, Mt 8:20; Mk 12:41-44] Love for the poor is even one of the motives for the duty of working so as to "be able to give to those in need." [Eph 4:28] It extends not only to material poverty but also to the many forms of cultural and religious poverty. [Cf. CA 57] 
2445 Love for the poor is incompatible with immoderate love of riches or their selfish use: 
Come now, you rich, weep and howl for the miseries that are coming upon you. Your riches have rotted and your garments are moth-eaten. Your gold and silver have rusted, and their rust will be evidence against you and will eat your flesh like fire. You have laid up treasure for the last days. Behold, the wages of the laborers who mowed your fields, which you kept back by fraud, cry out; and the cries of the harvesters have reached the ears of the Lord of hosts. You have lived on the earth in luxury and in pleasure; you have fattened your hearts in a day of slaughter. You have condemned, you have killed the righteous man; he does not resist you. [Jas 5:1-6] 
2446 St. John Chrysostom vigorously recalls this: "Not to enable the poor to share in our goods is to steal from them and deprive them of life. The goods we possess are not ours, but theirs." [St. John Chrysostom, Hom. in Lazaro 2, 5: PG 48, 992] "The demands of justice must be satisfied first of all; that which is already due in justice is not to be offered as a gift of charity": [AA 8 # 5] 
When we attend to the needs of those in want, we give them what is theirs, not ours. More than performing works of mercy, we are paying a debt of justice. [St. Gregory the Great, Regula Pastoralis. 3, 21: PL 77, 87]
2447 The works of mercy are charitable actions by which we come to the aid of our neighbor in his spiritual and bodily necessities. [Cf. Isa 58:6-7; Heb 13:3] Instructing, advising, consoling, comforting are spiritual works of mercy, as are forgiving and bearing wrongs patiently. The corporal works of mercy consist especially in feeding the hungry, sheltering the homeless, clothing the naked, visiting the sick and imprisoned, and burying the dead. [Cf. Mt 25:31-46] Among all these, giving alms to the poor is one of the chief witnesses to fraternal charity: it is also a work of justice pleasing to God: [Cf. Tob 4:5-11; Sir 17:22; Mt 6:2-4] [1460, 1038, 1969]
He who has two coats, let him share with him who has none and he who has food must do likewise. [Lk 3:11] But give for alms those things which are within; and behold, everything is clean for you. [Lk 11:41] If a brother or sister is ill-clad and in lack of daily food, and one of you says to them, "Go in peace, be warmed and filled," without giving them the things needed for the body, what does it profit? [Jas 2:15-16; cf. 1 Jn 3:17] 
2448 "In its various forms - material deprivation, unjust oppression, physical and psychological illness and death - human misery is the obvious sign of the inherited condition of frailty and need for salvation in which man finds himself as a consequence of original sin. This misery elicited the compassion of Christ the Savior, who willingly took it upon himself and identified himself with the least of his brethren. Hence, those who are oppressed by poverty are the object of a preferential love on the part of the Church which, since her origin and in spite of the failings of many of her members, has not ceased to work for their relief, defense, and liberation through numerous works of charity which remain indispensable always and everywhere." [CDF, instruction, Libertatis conscientia, 68]  
2449 Beginning with the Old Testament, all kinds of juridical measures (the jubilee year of forgiveness of debts, prohibition of loans at interest and the keeping of collateral, the obligation to tithe, the daily payment of the day-laborer, the right to glean vines and fields) answer the exhortation of Deuteronomy: "For the poor will never cease out of the land; therefore I command you, 'You shall open wide your hand to your brother, to the needy and to the poor in the land.'" [Deut 15:11] Jesus makes these words his own: "The poor you always have with you, but you do not always have me." [Jn 12:8] In so doing he does not soften the vehemence of former oracles against "buying the poor for silver and the needy for a pair of sandals...," but invites us to recognize his own presence in the poor who are his brethren: [Am 8:6; cf. Mt 25:40] 
When her mother reproached her for caring for the poor and the sick at home, St. Rose of Lima said to her: "When we serve the poor and the sick, we serve Jesus. We must not fail to help our neighbors, because in them we serve Jesus. [P. Hansen, Vita mirabilis (Louvain, 1668)] 
2450 "You shall not steal" (Ex 20:15; Deut 5:19). "Neither thieves, nor the greedy..., nor robbers will inherit the kingdom of God" (1 Cor 6:10).
2451 The seventh commandment enjoins the practice of justice and charity in the administration of earthly goods and the fruits of men's labor.
2452 The goods of creation are destined for the entire human race. The right to private property does not abolish the universal destination of goods.
2453 The seventh commandment forbids theft. Theft is the usurpation of another's goods against the reasonable will of the owner.
2454 Every manner of taking and using another's property unjustly is contrary to the seventh commandment. The injustice committed requires reparation. Commutative justice requires the restitution of stolen goods.
2455 The moral law forbids acts which, for commercial or totalitarian purposes, lead to the enslavement of human beings, or to their being bought, sold or exchanged like merchandise.
2456 The dominion granted by the Creator over the mineral, vegetable, and animal resources of the universe cannot be separated from respect for moral obligations, including those toward generations to come.
2457 Animals are entrusted to man's stewardship; he must show them kindness. They may be used to serve the just satisfaction of man's needs.
2458 The Church makes a judgment about economic and social matters when the fundamental rights of the person or the salvation of souls requires 17. She is concerned with the temporal common good of men because they are ordered to the sovereign Good, their ultimate end.
2459 Man is himself the author, center, and goal of all economic and social life. The decisive point of the social question is that goods created by God for everyone should in fact reach everyone in accordance with justice and with the help of charity.
2460 The primordial value of labor stems from man himself, its author and beneficiary. By means of his labor man participates in the work of creation. Work united to Christ can be redemptive.
2461 True development concerns the whole man. It is concerned with increasing each person's ability to respond to his vocation and hence to God's call (cf. CA 29).
2462 Giving alms to the poor is a witness to fraternal charity: it is also a work of justice pleasing to God.
2463 How can we not recognize Lazarus, the hungry beggar in the parable (cf. Lk 17:19-31), in the multitude of human beings without bread, a roof or a place to stay? How can we fail to hear Jesus: "As you did it not to one of the least of these, you did it not to me" (Mt 25:45)?