Jerome
Catena Aurea · Matthäusevangelium 18
Moreover if thy brother shall trespass against thee, go and tell him his fault between thee and him alone: if he shall hear thee, thou hast gained thy brother. But if he will not hear thee, then take with thee one or two more, that in the mouth of two or three witnesses every word may be established. And if he shall neglect to hear them, tell it unto the Church: but if he neglect to hear the Church, let him be unto thee as an heathen man and a Publican.
If then your brother have sinned against you, or hurt you in any matter, you have power, indeed must needs forgive him, for we are charged to forgive our debtors their debts. But if a man sin against God, it is no longer in our decision. But we do all tho contrary of this; where God is wronged we are merciful, where the affront is to ourselves we prosecute the quarrel.