For if you forgive men their trespasses, your heavenly Father will also forgive you:
All Commentaries on Matthew 6:14 Go To Matthew 6
Augustine of Hippo
And certainly we should not heedlessly neglect to call attention to the fact that of all the pronouncements in which the Lord has ordered us to pray, he has deliberately attached a very special commendation to the pronouncement that deals with the forgiving of sins. In this pronouncement he wished us to be merciful because that is the only prescribed means of avoiding miseries. Indeed, in no other petition do we pray in such a manner as to make a kind of covenant with the Lord, for we say, “Forgive us as we also forgive.” If we default in this covenant, the whole petition is fruitless, for he says, “For if you forgive men their trespasses, your heavenly Father also will forgive you; but if you do not forgive men their trespasses, neither will your Father forgive your trespasses.” .