What are you saying, O man? …
You remember wrongs which you brother has done to you, while you sharpen a knife to use against him, devise mischief against him, and bear malicious poison in your heart, and yet you cry out to God: Forgive me my debts, even as I, too, have forgiven my debtor?
Have you come to…receive Grace, or to draw down His wrath upon yourself? To gain forgiveness of sins, or to add to your sins? To obtain salvation or punishment?
Do you not see that we give each other the kiss of peace at that fearful hour precisely in order that, having rejected every bond of iniquity (Isaiah 58:6) and hard-heartedness, we might draw near to the Master with a pure heart? What are you doing, O man?
The six-winged Angels are ministering and covering the mystical Table, the Cherubim are standing around and exclaiming the Thrice-Holy Hymn with clear voices, the Seraphim are bowing their heads with reverence, the Hierarch is propitiating God on your behalf—all of them concentrating on the proceedings with fear and trembling.
The Lamb of God is being sacrificed, the Holy Spirit is descending from on high, the Angels are running about all the people unseen as they note down and register the souls of the Faithful.
Do you not shudder at the disdain that you show and at the kiss of Judas that you give to your brother, concealing in your heart the recollection of wrongs committed many years ago and the pernicious venom of the serpent against your brother?
How can you not shudder and fall down when you say to Him Who knows the secrets of the heart: Forgive me, even as I, too, have forgiven my brother?
In what way does such a prayer differ from a curse? Why, in saying this, you contradict yourself: If I pardon, pardon me; if I forgive, forgive me; if I show sympathy, show sympathy to me;
if I harbor a grudge against my fellow-servant, harbor one against me; if I am angry, be angry with me; with what measure I measure, let it be measured to me; if I forgive with hypocrisy, may I be shown mercy with hypocrisy.
I shall pronounce the verdict against myself, O Master. For I have heard Thy fearful voice, which says: For with what measure ye mete, it shall be measured to you again (St. Matthew 7:2); and: If ye forgive not men their trespasses, neither will your Father forgive you (St. Matthew 6:15).
Convinced by the assertion of these unerring words of Thine, I have pardoned and forgiven those who have sinned against me. Therefore, O Master, pardon me, just as I, too, have pardoned my fellow-servants.
Anastasius of Sinai (7th Century): A Homily on the Holy Eucharist and on Not Judging Others or Remembering Wrongs, PG 89, 825A-849C @ OCIC.