CIC 982 There is no offense, however serious, that the Church cannot forgive. “There is no one, however wicked and guilty, who may not confidently hope for forgiveness, provided his repentance is honest.”1 Christ who died for all men desires that in his Church the gates of forgiveness should always be open to anyone who turns away from sin.2

CIC 2227 Children in turn contribute to the growth in holiness of their parents.3 Each and everyone should be generous and tireless in forgiving one another for offenses, quarrels, injustices, and neglect. Mutual affection suggests this. The charity of Christ demands it.4

CIC 2843 Thus the Lord’s words on forgiveness, the love that loves to the end,5 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.”6 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.

CIC 2845 There is no limit or measure to this essentially divine forgiveness,7 whether one speaks of “sins” as in Luke (11:4), “debts” as in Matthew (6:12). We are always debtors: “Owe no one anything, except to love one another.”8 The communion of the Holy Trinity is the source and criterion of truth in every relation ship. It is lived out in prayer, above all in the Eucharist.9
God does not accept the sacrifice of a sower of disunion, but commands that he depart from the altar so that he may first be reconciled with his brother. For God can be appeased only by prayers that make peace. To God, the better offering is peace, brotherly concord, and a people made one in the unity of the Father, Son, and Holy Spirit.10

1 Roman Catechism I, 11, 5.
2 Cf. Mt 18:21-22.
3 Cf. GS 48 # 4.
4 Cf. Mt 18:21-22; Lk 17:4.
5 Cf. Jn 13:1.
6 Cf. Mt 18:23-35.
7 Cf. Mt 18:21-22; Lk 17:3-4.
8 Rom 13:8.
9 Cf. Mt 5:23-24; 1 Jn 3:19-24.
10 St. Cyprian, De Dom. orat. 23: PL 4, 535-536; cf. Mt 5:24.