The controversy over Amoris Laetitia has raised the question as to whether it might be impossible for a divorced and remarried couple to refrain from sex, as the Church teaches they must. They do not have a valid Sacrament of Marriage, due to the prior valid marriage of one or both of the couple. So their sexual acts are extra-marital and also a form of adultery (since at least one of them is validly married to someone else). Ideally, they should separate, since they are not married in the eyes of God. But the Church teaches that, in some circumstances, they might live in the same home, for the sake of the children, but refrain from all sexual activity.
Amoris Laetitia does not state that it is impossible for some couples to live in continence (abstaining from sex). But some commentators and perhaps some Bishops have drawn that mistaken conclusion. I think Pope Francis was saying that some persons, for various reasons (explained in the CCC) that mitigate culpability, might have great difficulty in leaving their second union and/or great difficulty in abstaining from sex continuously. But he was NOT saying that these couples absolutely cannot do what is morally required and therefore they are morally excused. That is a misinterpretation.
The Magisterium has taught, regarding a validly married couple who must abstain from sex for some medical reason (e.g. that a subsequent pregnancy would be dangerous to the health of the mother), that continence is not impossible. God’s grace is always available to help us avoid grave sin, even if the fallen sinner, at times, may think that a grave sin before him is seemingly nearly impossible to avoid.
The teaching is found in Address to Midwives, Pope Pius XII, 1951 (my translation), as follows.
42. It will be objected that such an abstention is impossible, that such a heroism is asking too much. You will hear this objection raised; you will read it everywhere. Even those who should be in a position to judge very differently, by reason of either their duties or their qualifications, are ever ready to bring forward the following argument: “No one is obliged to do what is impossible, and it may be presumed that no reasonable legislator can will his law to oblige to the point of impossibility. But, for husbands and wives, long periods of abstention are impossible. Therefore they are not obliged to abstain; Divine law cannot have this meaning.”
43. In such a manner, from partially true premises, one arrives at a false conclusion. To convince oneself of this, it suffices to invert the terms of the argument: “God does not oblige anyone to do what is impossible. But God obliges husband and wife to abstinence if their union cannot be completed according to the laws of nature. Therefore, in this case, abstinence is possible.” To confirm this argument, there can be brought forward the doctrine of the Council of Trent, which teaches, in the chapter on that observance which is necessary and possible, in reference to a passage from St. Augustine: “God does not command the impossible, but when He commands, He warns you to do what you can, and to ask for the grace for what you cannot do, and He helps you so that you may be able”. [Council of Trent, Session 6, Chapter II, Denzinger, n. 804; St. Augustine, On Nature and Grace, chapter 43, n. 50.]
44. Do not be disturbed, therefore, in the practice of your profession and apostolate, by this grand talk of impossibility. Do not be disturbed in your internal judgment, nor in your external conduct. Never lend yourselves to anything which is contrary to the law of God and to your Christian conscience! It would be a wrong toward men and women of our age to judge them incapable of continuous heroism. Nowadays, for many a reason, — perhaps constrained by dire necessity, or even at times oppressed by injustice — heroism is exercised to a degree and to an extent that, in the past, would have been thought impossible. Why, then, if circumstances truly demand it, should this heroism stop at the limits prescribed by the passions and the inclinations of nature? It is clear: he who does not want to master himself is not able to do so, and he who wishes to master himself, relying only upon his own powers, without sincerely and perseveringly seeking help, will be miserably deceived.
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