A penitent is an undisgraced convict. Repentance is reconciliation with the Lord by the practice of good deeds contrary to the sins.

St. John Climacus

By resolving to make one's confession, the soul is thereby held from sinning as by a bridle. For what we do not confess, that we do fearlessly as though in the dark.

St. John Climacus

In the words of the psalmist, "As you lie in bed, repent of what you say in your heart" (Ps. 4:4 LXX), that is, repent in the stillness of the night, remembering the lapses that occurred in the confusion of the day and disciplining yourself in hymns and spiritual songs (cf. Col. 3:16) – in other words, teaching yourself to persist in prayer and psalmody through attentive meditation on what you read. For the practice of the moral virtues is effectuated by meditating on what has happened during the day, so that during the stillness of the night we can become aware of the sins we have committed and can grieve over them.

St. Peter of Damascus

God is loving to man, and loving in no small measure. For say not, I have committed fornication and adultery: I have done dreadful things, and not once only, but often: will He forgive? Will He grant pardon? Hear what the Psalmist says: "How great is the multitude of Your goodness, O Lord!" 

Your accumulated offenses surpass not the multitude of God’s mercies: your wounds surpass not the great Physician’s skill. Only give yourself up in faith: tell the Physician your ailment: say thou also, like David: "I said, I will confess me my sin unto the Lord": and the same shall be done in your case, which he says immediately: "And you forgave the wickedness of my heart.”

St. Cyril of Jerusalem

It is not enough to simply make your confession to the Spiritual Father; you must also truly repent of what you have done.

St. Paisios of Mount Athos