Please read this passage before reading the homily.
My sisters and brothers,
What is the kingdom of heaven like? It is the forgiveness of all the evils of the whole world.
The Gospel speaks of a huge amount of debt, something like the national debt. The ancient texts speak of seventy times seven, which is to say a perfect number. The number seven symbolizes perfection and the number multiplied by itself signifies the perfection of perfection.
In the book of Genesis, in the lifetime of Lamec, the sixth generation after Cain, the evil of the world had filled up the world completely and Lamec said he would take revenge for evils done seventy times seven times.
In the Gospel, the Lord says that we have to forgive seventy times seven, which is to say, to forgive the totality of the evil of others completely and perfectly.
We need to undo the revenge of Lamec completely and replace it with the forgiveness of Christ perfectly, which is to say, seventy times seven, or up to the fulness of the goodness of God.
We usually forgive only partly offense committed against us, but we are obligated to forgive everyone completely and perfectly.
God always forgives the totality of our evil and forgives our offenses completely because this is what his kingdom is. Seventy times seven means for ever and for everyone, without exception. If we owe something like the national debt, God still forgives us, and we have an obligation to forgive everyone else.