Amoris laetitia: "A subject may ... be in a concrete situation which does not allow him or her to act differently and decide otherwise without further sin." The Filial Correction accordingly condemned the proposition that a person may, while he obeys a divine prohibition, sin against God by that very act of obedience.
In the second volume of his 'theological' Space Trilogy (Chapter 9), C S Lewis portrays one of the Enemy attempting to persuade the future Matriarch of another the planet, a prelapsarian Eve, to break the one commandment God has given her which is commanded solely in order to create a space in which obedience can be practised for the sake of obedience without having any utilitarian advantage. Other commandments, such as Not Killing, may need little justifying because they give us all security; so God has given that planet one commandment which has as its only purpose the making of an act of obedience.
'Satan', on Lewis's fictional planet, attempts to persuade 'Eve' by arguing that 'God' may give a commandment, while actually desiring that the created rational being will disobey it. "There might be a commanding which he wished you to break". "The wrong kind of obeying itself can be a disobeying". Thus, there may a commandment of God which He actually wishes a human to break. In other words, God may give a Law, but beyond that command God has a higher will which, without saying so, He really desires to be discerned and to be obeyed at the expense of the given and uttered and known Law.
God gave you a Law, but he really wants you to break it.
That is one of Satan's most Cunning Ploys, as cleverly detected and described by Lewis. And it is precisely the Infernal device by which the Enemy subsequently, in our own time and on this planet, has promoted Adultery through Amoris laetitia. It is the notion that, beyond and above "Thou shalt not commit Adultery", there is a higher Divine Will which, at least on occasions, trumps it. Thus AL tells 'remarried divorcees': "You should have adulterous intercourse with X, who is not your lawful spouse, because otherwise (s)he may be tempted to be unfaithful to you and walk out, which would be a tragedy for the children you have had together since your civil marriage." The wrong kind of obeying itself can be a disobeying, as Lewis's Devil puts it. (It is, of course, essentially the old Satanic temptation to do evil so that good may result; that the end justifies the means.)
Blessed Paul VI is not often admired by Traddies; I think he should be given more credit for his courage in issuing Humanae vitae than he sometimes receives. And I am convinced that his own frank honesty in admitting that, on his own watch, the Smoke of Satan had crept through some crack into the Temple of God, deserves credit. OK, he was a po' Amletico, as S John XXIII observed, but he was not blind to his principal duty, as Bishop of Rome, to uphold the integrity of Tradition; to resist novitates. Montini was not, indeed, a Leo or a Hildebrand; but I am not convinced that he was a Honorius.
Speaking only for myself, I feel that if PF were able to bring himself manfully to concede that the Smoke of Satan did indeed percolate through some fissure into the final section of his Exhortation Amoris laetitia, he would be shown to be a vastly bigger and more honourable man than, despite all his bluster, he seems. As things are, he appears to me to fall some fair distance short of the standards of courage, humility, and honesty, set by Papa Montini.