Cyprian of Carthage, Three Books of Testimonies Against the Jews III.23: That when we have received a wrong, we must remit and forgive it

In the Gospel, in the daily prayer: “Forgive us our debts, even as we forgive our debtors.” Also according to Mark: “And when ye stand for prayer, forgive, if ye have ought against any one; that also your Father who is in heaven may forgive you your sins. But if ye do not forgive, neither will your Father which is in heaven forgive you your sins.” Also in the same place: “In what measure ye mete, in that shall it be measured to you again.”