The marriage of those who have been baptized is, in addition, invested with the dignity of a sacramental sign of grace, for it represents the union of Christ and His Church.
With regard to man’s innate drives and emotions, responsible parenthood means that man’s reason and will must exert control over them.
Not much experience is needed to be fully aware of human weakness and to understand that human beings—and especially the young, who are so exposed to temptation—need incentives to keep the moral law, and it is an evil thing to make it easy for them to break that law.
Another effect that gives cause for alarm is that a man who grows accustomed to the use of contraceptive methods may forget the reverence due to a woman, and, disregarding her physical and emotional equilibrium, reduce her to being a mere instrument for the satisfaction of his own desires, no longer considering her as his partner whom he should surround with care and affection.
Since the Church did not make either of these laws, she cannot be their arbiter—only their guardian and interpreter. It could never be right for her to declare lawful what is in fact unlawful, since that, by its very nature, is always opposed to the true good of man.
This is especially clear in the practice of periodic continence. Self-discipline of this kind is a shining witness to the chastity of husband and wife and, far from being a hindrance to their love of one another, transforms it by giving it a more truly human character.
We would call their attention to the need to create an atmosphere favorable to the growth of chastity so that true liberty may prevail over license and the norms of the moral law may be fully safeguarded.
We have no wish at all to pass over in silence the difficulties, at times very great, which beset the lives of Christian married couples. For them, as indeed for every one of us, “the gate is narrow and the way is hard, that leads to life.”
Note: I am not Catholic, but I absolutely love the depth at which Catholic teaching is able to take controversial issues. I do not believe that we are saved by baptism or–God forbid– saved by works, but we can learn a lot from each other if we are willing to listen.