§2843
Prayer › … › V. "And Forgive Us Our Trespasses, As We Forgive Those Who Trespass Against Us"
. . . As we forgive those who trespass against us
Thus the Lord's words on forgiveness, the love that loves to the end, become a living reality. The parable of the merciless servant, which crowns the Lord's teaching on ecclesial communion, ends with these words: "So also my heavenly Father will do to every one of you, if you do not forgive your brother from your heart." It is there, in fact, "in the depths of the heart," that everything is bound and loosed. It is not in our power not to feel or to forget an offense; but the heart that offers itself to the Holy Spirit turns injury into compassion and purifies the memory in transforming the hurt into intercession.
Source: Catechism of the Catholic Church (Vatican.va)