The soul that really loves God and Christ, though it may do ten thousand righteousnesses, esteems itself as having wrought nothing, by reason of its insatiable aspiration after God. Though it should exhaust the body with fastings, with watchings, its attitude towards the virtues is as if it had not even begun to labor for them.
Christians should judge no one, neither an open harlot, nor sinners, nor dissolute people, but should look upon all with simplicity of soul and a pure eye. Purity of heart, indeed, consists in seeing sinful and weak men and having compassion for them and being merciful.
He who wants to cross the spiritual sea is long-suffering, humble, vigilant and self-controlled. If he impetuously embarks on it without these four virtues, he agitates his heart, but cannot cross.
He who knows himself pays no heed to the sins of others, but looks at his own and is always repenting over them; he reflects concerning himself, and condemns himself, and does not interfere in anything apart from his own position.
Those who have sinned must not despair. Let that never be. For we are condemned not for the multitude of evils, but because we do not want to repent...
The most important thing in any good effort and the height of all activities is to persevere in prayer, by means of which we can always acquire through supplication the other virtues from God as well.
I suppose that it is sometimes better to fall oneself and rise, than to judge one's neighbor; because one who has sinned is incited to self-abasement and repentance, while he who judges one who has sinned becomes hardened in an illusion about himself and in pride. Therefore everyone must guard himself, as much as possible, so as not to judge.
This prayer should never be absent from you: 'Lord Jesus Christ, Son and Logos of the living God, through the Theotokos and all the Saints, have mercy upon me, Thy sinful and unworthy servant.' (This is the actual Jesus Prayer: 'O LORD JESUS CHRIST, SON OF GOD, HAVE MERCY UPON ME, A SINNER.') Always say this prayer both with your mouth and with your mind, day and night, wherever you may be, whether eating, walking, working, or sitting. Always meditate on it, as it benefits you a great deal, frees you here from every evil, delivers you there from eternal Hell, and renders you worthy of going to Paradise, our heavenly country.
There is a sin which is always 'unto death' [1 Jn 5:16]; the sin which we have not repented. Even a saint's prayers will not be heard for the unrepented sin. The person who repents correctly does not imagine that his sins are cancelled through his own effort; but knows that through this effort he makes peace with God.