By St. Seraphim of Sarov
Just as the Lord is concerned about our salvation, so does the devil, the slayer of men, concern himself about bringing the soul of man to despair.
Judas the betrayer was faint-hearted and inexperienced in struggle, which is why the devil, seeing him in a state of despair, attacked and persuaded him to hang himself.
Peter, the formidable rock, falling into great sin and experienced in struggle, did not despair and did not lose the presence of the Spirit, rather he shed bitter tears from a warm heart and, seeing that, the devil fled from him as though burned by fire.
Thus, brethren, the Venerable Antiochus teaches that when despair befalls us, we should not succumb to it but, strengthened and enveloped by Holy Faith, say with great bravery to the cunning spirit [the devil]: "What have you to do with us, O apostate from God, fugitive from heaven and a slave of evil! You are unable to inspire us to do anything; for Christ, the Son of God, has authority over us and over all. And you, O murderer, depart from us! Strengthened by His Honorable Cross, we trample upon your serpent's head."