The following are excerpts from the text; for the complete encyclical click here Vatican - Casti Connubii

Venerable Brethren and Beloved Children, Health and Apostolic Benediction.

How great is the dignity of chaste wedlock, Venerable Brethren, may be judged best from this that Christ Our Lord, Son of the Eternal Father, having assumed the nature of fallen man, not only, with His loving desire of compassing the redemption of our race, of ordained it in an especial manner as the principle and foundation of domestic society and therefore of all human intercourse, but also raised it to the rank of a truly and great sacrament the New Law, restored it to the original purity of its divine institution, and accordingly entrusted all its discipline and care to His spouse the Church.

2. In order, however, that amongst men of every nation and every age the desired fruits may be obtained from this renewal of matrimony, it is necessary, first of all, that men's minds be illuminated with the true doctrine of Christ regarding it; and secondly, that Christian spouses, the weakness of their wills strengthened by the internal grace of God, shape all their ways of thinking and of acting in conformity with that pure law of Christ so as to obtain true peace and happiness for themselves.

4. We have decided therefore to speak to you, Venerable Brethren, and through you to the whole Church of Christ and indeed to the whole human race, on the nature and dignity of Christian marriage, on the advantages and benefits which accrue from it to the family and to human society itself…

5. And to begin with that same Encyclical, which is wholly concerned in vindicating the divine institution of matrimony, its sacramental dignity, and its perpetual stability, let it be repeated as an immutable and inviolable fundamental doctrine that matrimony was not instituted or restored by man but by God; not by man were the laws made to strengthen and confirm and elevate it but by God, the Author of nature, and by Christ Our Lord by Whom nature was redeemed, and hence these laws cannot be subject to any human decrees or to any contrary pact even of the spouses themselves. This is the doctrine of Holy Scripture;[2] this is the constant tradition of the Universal Church; this the solemn definition of the sacred Council of Trent, which declares and establishes from the words of Holy Writ itself that God is the Author of the perpetual stability of the marriage bond, its unity and its firmness.[3]

41. Nevertheless, since it is a law of divine Providence in the supernatural order that men do not reap the full fruit of the Sacraments which they receive after acquiring the use of reason unless they cooperate with grace, the grace of matrimony will remain for the most part an unused talent hidden in the field unless the parties exercise these supernatural powers and cultivate and develop the seeds of grace they have received. If, however, doing all that lies with their power, they cooperate diligently, they will be able with ease to bear the burdens of their state and to fulfill their duties. By such a sacrament they will be strengthened, sanctified and in a manner consecrated. For, as St. Augustine teaches, just as by Baptism and Holy Orders a man is set aside and assisted either for the duties of Christian life or for the priestly office and is never deprived of their sacramental aid, almost in the same way (although not by a sacramental character), the faithful once joined by marriage ties can never be deprived of the help and the binding force of the sacrament. Indeed, as the Holy Doctor adds, even those who commit adultery carry with them that sacred yoke, although in this case not as a title to the glory of grace but for the ignominy of their guilty action, "as the soul by apostasy, withdrawing as it were from marriage with Christ, even though it may have lost its faith, does not lose the sacrament of Faith which it received at the laver of regeneration."[41]

42. These parties, let it be noted, not fettered but adorned by the golden bond of the sacrament, not hampered but assisted, should strive with all their might to the end that their wedlock, not only through the power and symbolism of the sacrament, but also through their spirit and manner of life, may be and remain always the living image of that most fruitful union of Christ with the Church, which is to venerated as the sacred token of most perfect love.

43. All of these things, Venerable Brethren, you must consider carefully and ponder over with a lively faith if you would see in their true light the extraordinary benefits on matrimony - offspring, conjugal faith, and the sacrament. No one can fail to admire the divine Wisdom, Holiness and Goodness which, while respecting the dignity and happiness of husband and wife, has provided so bountifully for the conservation and propagation of the human race by a single chaste and sacred fellowship of nuptial union.

49. To begin at the very source of these evils, their basic principle lies in this, that matrimony is repeatedly declared to be not instituted by the Author of nature nor raised by Christ the Lord to the dignity of a true sacrament, but invented by man. Some confidently assert that they have found no evidence of the existence of matrimony in nature or in her laws, but regard it merely as the means of producing life and of gratifying in one way or another a vehement impulse; on the other hand, others recognize that certain beginnings or, as it were, seeds of true wedlock are found in the nature of man since, unless men were bound together by some form of permanent tie, the dignity of husband and wife or the natural end of propagating and rearing the offspring would not receive satisfactory provision. At the same time they maintain that in all beyond this germinal idea matrimony, through various concurrent causes, is invented solely by the mind of man, established solely by his will.

50. How grievously all these err and how shamelessly they leave the ways of honesty is already evident from what we have set forth here regarding the origin and nature of wedlock, its purposes and the good inherent in it. The evil of this teaching is plainly seen from the consequences which its advocates deduce from it, namely, that the laws, institutions and customs by which wedlock is governed, since they take their origin solely from the will of man, are subject entirely to him, hence can and must be founded, changed and abrogated according to human caprice and the shifting circumstances of human affairs; that the generative power which is grounded in nature itself is more sacred and has wider range than matrimony - hence it may be exercised both outside as well as within the confines of wedlock, and though the purpose of matrimony be set aside, as though to suggest that the license of a base fornicating woman should enjoy the same rights as the chaste motherhood of a lawfully wedded wife.

51. Armed with these principles, some men go so far as to concoct new species of unions, suited, as they say, to the present temper of men and the times, which various new forms of matrimony they presume to label "temporary," "experimental," and "companionate." These offer all the indulgence of matrimony and its rights without, however, the indissoluble bond, and without offspring, unless later the parties alter their cohabitation into a matrimony in the full sense of the law.

52. Indeed there are some who desire and insist that these practices be legitimatized by the law or, at least, excused by their general acceptance among the people. They do not seem even to suspect that these proposals partake of nothing of the modern "culture" in which they glory so much, but are simply hateful abominations which beyond all question reduce our truly cultured nations to the barbarous standards of savage peoples.

53. And now, Venerable Brethren, we shall explain in detail the evils opposed to each of the benefits of matrimony. First consideration is due to the offspring, which many have the boldness to call the disagreeable burden of matrimony and which they say is to be carefully avoided by married people not through virtuous continence (which Christian law permits in matrimony when both parties consent) but by frustrating the marriage act. Some justify this criminal abuse on the ground that they are weary of children and wish to gratify their desires without their consequent burden. Others say that they cannot on the one hand remain continent nor on the other can they have children because of the difficulties whether on the part of the mother or on the part of family circumstances.

54. But no reason, however grave, may be put forward by which anything intrinsically against nature may become conformable to nature and morally good. purpose sin against nature and commit a deed which is shameful and intrinsically vicious.

55. Small wonder, therefore, if Holy Writ bears witness that the Divine Majesty regards with greatest detestation this horrible crime and at times has punished it with death. As St. Augustine notes, "Intercourse even with one's legitimate wife is unlawful and wicked where the conception of the offspring is prevented. Onan, the son of Juda, did this and the Lord killed him for it."[45]

56. Since, therefore, openly departing from the uninterrupted Christian tradition some recently have judged it possible solemnly to declare another doctrine regarding this question, the Catholic Church, to whom God has entrusted the defense of the integrity and purity of morals, standing erect in the midst of the moral ruin which surrounds her, in order that she may preserve the chastity of the nuptial union from being defiled by this foul stain, raises her voice in token of her divine ambassadorship and through Our mouth proclaims anew: any use whatsoever of matrimony exercised in such a way that the act is deliberately frustrated in its natural power to generate life is an offense against the law of God and of nature, and those who indulge in such are branded with the guilt of a grave sin.

57. We admonish, therefore, priests who hear confessions and others who have the care of souls, in virtue of Our supreme authority and in Our solicitude for the salvation of souls, not to allow the faithful entrusted to them to err regarding this most grave law of God; much more, that they keep themselves immune from such false opinions, in no way conniving in them. If any confessor or pastor of souls, which may God forbid, lead the faithful entrusted to him into these errors or should at least confirm them by approval or by guilty silence, let him be mindful of the fact that he must render a strict account to God, the Supreme Judge, for the betrayal of his sacred trust, and let him take to himself the words of Christ: "They are blind and leaders of the blind: and if the blind lead the blind, both fall into the pit.[46]

60. We are deeply touched by the sufferings of those parents who, in extreme want, experience great difficulty in rearing their children.

61. However, they should take care lest the calamitous state of their external affairs should be the occasion for a much more calamitous error. No difficulty can arise that justifies the putting aside of the law of God which forbids all acts intrinsically evil. There is no possible circumstance in which husband and wife cannot, strengthened by the grace of God, fulfill faithfully their duties and preserve in wedlock their chastity unspotted. This truth of Christian Faith is expressed by the teaching of the Council of Trent. "Let no one be so rash as to assert that which the Fathers of the Council have placed under anathema, namely, that there are precepts of God impossible for the just to observe. God does not ask the impossible, but by His commands, instructs you to do what you are able, to pray for what you are not able that He may help you."[48]

71. Furthermore, Christian doctrine establishes, and the light of human reason makes it most clear, that private individuals have no other power over the members of their bodies than that which pertains to their natural ends; and they are not free to destroy or mutilate their members, or in any other way render themselves unfit for their natural functions, except when no other provision can be made for the good of the whole body.

128. All these things which, Venerable Brethren, prompted by Our past solicitude We put before you, We wish according to the norm of Christian prudence to be promulgated widely among all Our beloved children committed to your care as members of the great family of Christ, that all may be thoroughly acquainted with sound teaching concerning marriage, so that they may be ever on their guard against the dangers advocated by the teachers of error, and most of all, that "denying ungodliness and worldly desires, they may live soberly and justly, and godly in this world, looking for the blessed hope and coming of the glory of the great God and Our Savior Jesus Christ."[98]

129. May the Father, "of whom all paternity in heaven and earth is named,"[99] Who strengthens the weak and gives courage to the pusillanimous and fainthearted; and Christ Our Lord and Redeemer, "the Institutor and Perfecter of the holy sacraments,"[100] Who desired marriage to be and made it the mystical image of His own ineffable union with the Church; and the Holy Ghost, Love of God, the Light of hearts and the Strength of the mind, grant that all will perceive, will admit with a ready will, and by the grace of God will put into practice, what We by this letter have expounded concerning the holy Sacrament of Matrimony, the wonderful law and will of God respecting it, the errors and impending dangers, and the remedies with which they can be counteracted, so that that fruitfulness dedicated to God will flourish again vigorously in Christian wedlock.

130. We most humbly pour forth Our earnest prayer at the Throne of His Grace, that God, the Author of all graces, the inspirer of all good desires and deeds,[101] may bring this about, and deign to give it bountifully according to the greatness of His liberality and omnipotence, and as a token of the abundant blessing of the same Omnipotent God, We most lovingly grant to you, Venerable Brethren, and to the clergy and people committed to your watchful care, the Apostolic Benediction.

Given at Rome, in Saint Peter's, this 31st day of December, of the year 1930, the ninth of Our Pontificate.

2001 Catholics Against Contraception