From The Ladder of Divine Ascent by St. John Climacus:
"You wish, or rather, have decided, to remove a splinter from someone? Very well, but do not go after it with a stick instead of a lancet for you will only drive it deeper. Rough speech and harsh gestures are the stick, while even-tempered instruction and patient repremand are the lancet. ‘Reprove, rebuke, exhort,’ says the Apostle (2 Tim 4:2), not ‘batter.’"
"Malice is an exponent of Scripture which twists the owrds of the Spirit to suit itself. Let the prayer of Jesus [i.e., the Lord’s Prayer, a.k.a. the Our Father] put it to shame, that prayer which cannot be uttered in the company of malice."
"If after great effort you still fail to root out this thorn, go to your enemy and apologize, if only with empty words whose insincereity may shame you. Then as conscience, like a fire, comes to give you pain, you may find that a sincere love of your enemy may come to life."
"A true sign of having completely mastered this putrefaction will come not when you pray for the man who offended you, not when you give him presents, not when you invite him to share a meal with you, but only when, on hearing of some catastrophe that has afflcited him in body or soul, you suffer and you lament for him as if for yourself."
"I have rebuked people who were engaged in slander, and, in self defense, these evildoers claimed to be acting out of love and concern for the victim of the slander. My answer to that was to say: ‘Then stop that kind of love, or else you will be making a liar out of him who declared, ‘I drove away the man who secretly slandered his neighbor’ (Ps. 100:5). If, as you insist, you love that man, then do not be making a mockery of him, but pray for him in secret, for this is the kind of love that is acceptable to the Lord. And remember – now I say this as something to be pondered, and do not start passing judgment on the offender – Judas was one of the company of Christ’s disciples and the robber was in the company of killers. Yet what a turnabout there was when the decisive moment arrived!"
"Fire and water do not mix, neither can you mix judgment of others with the desire to repent. If a man commits a sin before you at the very moment of his death, pass no judgment, because the judgment of God is hidden from men. It has happened that men have sinned greatly in the open but have done greater good deeds in secret, so that those who would disparage them have been fooled, with smoke instead of sunlight in their eyes. So listen to me, all you accountants of other people’s faults, listen well: for if, as is certain, it is true that ‘you shall be judged with the judgment you have used yourselves’ (Matt. 7:2), then whatever sin of body or spirit that we ascribe to our neighbor will surely fall into ourselves."
[…]
"You can always recognize people who are malicious and slanderous. They are filled with the spirit of hatred. Gladly and without a qualm they slander the teaching, the doings and the virtues of their neighbor. I have known men who secretly had committed very grave sins and had not been found out, yet cloaked in their supposed goodness they lashed out against people who had done something minor in public."
"To pass judgment on another is to usurp shamelessly a prerogative of God, and to condemn is to ruin one’s soul."
[…]
"Do not condemn. Not even if your very eyes are seeing something, for they may be deceived."