St. Cyril of Jerusalem: If you have anything against any man, forgive it...

If you have anything against any man, forgive it: you come here to receive forgiveness of sins, and thou also must forgive him that has sinned against you. 

Else with what face will you say to the Lord, "Forgive me my many sins," if you have not yourself forgiven your fellow-servant even his little sins.

St. Cyril of Jerusalem