Once upon a time, the devil appeared to three monks and said: If he gave you power to change something from the past, what would you change?
The first of them had great apostolic fervor, and he answered, “I would prevent you from making Adam and Eve fall into sin, so that mankind could not part ways from God.”
The second of them was a man full of mercy and said to him, “I would hinder you from God and condemn yourself forever.”
The third of them was the simplest and, instead of answering the tempter, he fell on his knees, made the sign of the cross and prayed saying, “Lord, deliver me from the devil of what could have been and was not.”
The devil, giving a loud scream and trembling in pain, flew away.
The other two, astonished, said to him, “Brother, why did you react like that?” “. He answered them:
“First of all, because we must NEVER DIALOGUE with the enemy.” Secondly, because there is no power in this world that can CHANGE the past. Third place, because Satan’s interest was not that we test our VIRTUE, but that, stuck in the PAST, we neglect the present, because it is the only time in which God gives us His grace and we can cooperate with it to FULFILL His will. Of all the demons, the one that traps men the most and prevents them from being happy is the one that CAN BE AND WASN’T. The past is left to God’s Mercy and the future to His Providence. Only the present is in our hands.”
In the "Wilds of Wisconsin & Cornfields of Iowa" 