The Father William Most Collection
Attachment to Sin
What is there to do to be free from attachment to venial sin, which is required to gain a plenary indulgence? It is a gap in one's purpose of amendment, as if he said to himself: "I do not intend to commit many or great sins. But I reserve a bit for myself: If it gets hard to join in a conversation without talking against neighbor -- I will do it. If it gets too hard to stick to the truth: I will lie. There are many other possibilities.
A person who has such an attitude does not have to do it consciously: it is merely the standard, habitual attitude of his soul: it sets limits to his response to God. It is as if he put a clamp on his heart, which lets it expand only so far, and no farther.
That gap not only blocks reception of a plenary indulgence (only a partial indulgence would be received) - it blocks all actual spiritual growth, no matter how many Masses a person may attend, or other good things. It is sad to see people who in general are very good ,yet making no real growth. Soon a retreat is one time to examine one's attitudes: Do I really mean to hold out? Even if one does not realize he has such a defect, it still harms him. He can begin to really grow only when he finds he has the attitude and clean sit up.