From St. Augustine of Hippo:
And who's the sort of person who perishes from hope? I'll sketch you his portrait: the kid of person who says to himself, "Now God has promised to pardon all who turn away from their sins - the very day they are converted he will forget all their iniquities. So I will do whatever I want, and whenever I want to I will have a conversion, and what I have done will be blotted out." What are we to say to that? That God does NOT heal the repentant whenever they turn back to him? God does forgive everything that has gone before. If we deny it, we contradict the divine indulgence, we clash head on with the words of the prophets, and we are struggling against the utterances of God.
Reminds me of Matthew 20, where the workers hired at the end of the day are paid the same wage as those hired at the beginning of the day. Let us not be jealous of God's mercy, lest we struggle against God himself.