The Devil cunningly induces us – instead of irritating us against himself – to notice our neighbors’ sins, to make us spiteful and angry with others, and to awaken our contempt towards them, thus keeping us in enmity with our neighbors, and with the Lord God Himself. Therefore, we must despise the sins, the faults themselves, and not our brother who commits them at the Devil’s instigation, through infirmity and habit; we must pity him, and gently and lovingly instruct him,as one who forgets himself, or who is sick, as a prisoner and the slave of his sin. But our animosity, our anger towards the sinner only increases his sickness, oblivion, and spiritual bondage, instead of lessening them.
-- St John of Kronstadt, My Life in Christ
H/T: Dover Beach