On Christian Marriage
Pope Pius XI - 1930
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.
58. As regards the evil use of matrimony, to pass over the arguments which are shameful, not infrequently others that are false and exaggerated are put forward. Holy Mother Church very well understands and clearly appreciates all that is said regarding the health of the mother and the danger to her life. And who would not grieve to think of these things? Who is not filled with the greatest admiration when he sees a mother risking her life with heroic fortitude, that she may preserve the life of the offspring which she has conceived? God alone, all bountiful and all merciful as He is, can reward her for the fulfillment of the office allotted to her by nature, and will assuredly repay her in a measure full to overflowing.
59. Holy Church knows well that not infrequently one of the parties is sinned against rather than sinning, when for a grave cause he or she reluctantly allows the perversion of the right order. In such a case, there is no sin, provided that, mindful of the law of charity, he or she does not neglect to seek to dissuade and to deter the partner from sin. Nor are those considered as acting against nature who in the married state use their right in the proper manner although on account of natural reasons either of time or of certain defects, new life cannot be brought forth. For in matrimony as well as in the use of the matrimonial rights there are also secondary ends, such as mutual aid, the cultivating of mutual love, and the quieting of concupiscence which husband and wife are not forbidden to consider so long as they are subordinated to the primary end and so long as the intrinsic nature of the act is preserved.
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.”
St. Thomas Aquinas
Referring to contraception: “Hence, after the sin of homicide whereby a human life already in existence is destroyed, this type of sin appears to take next place, for by it the generation of human nature is impeded.” St. Thomas Aquinas, Summa contra gentiles, 3, 122.
1917 Code of Canon Law:
“If anyone for the sake of fulfilling sexual desire or with premeditated hatred does something to a man or a woman, or gives something to drink, so that he cannot generate or she cannot conceive or offspring be born, let him be held as a murderer.” Corpus iuris canonici, eds. A. L. Richter and A. Friedberg (Leipzig: Tauchnitz, 1881), 2, 794
The Roman Catechism (Catechism of the Council of Trent)
The Roman Catechism: “Whoever in marriage artificially prevents conception, or procures an abortion, commits a most serious sin: the sin of premeditated murder.” The Roman Catechism, Part II, Chap. 7, No. 13