Abba Macarius of Alexandria (+ ca. 393) warned against attempting to correct our peers.
PACHOMIUS asked him, “When brothers do not submit to the rule, is it right to correct them?”
Abba Macarius said to him, “Correct and judge justly those who are subject to you, but judge no one else.”
According to Joseph the Hesychast (+1959), the right response to faults in your fellow man – “even if you see him committing a mortal sin” – is to pray with sincere affection for him, standing as it were at his side.
SYMPATHIZE with him who does not have gifts. Don’t judge him because he doesn’t have any, saying he is a sinner, depraved, evil, a babbler, a thief, a fornicator, a liar.
If you acquire this knowledge, you will never be able to judge anyone, even if you see him committing a mortal sin, because you would say right away:
“He doesn’t have Your grace, my Christ, and that is why he sins.
“If You leave me, I shall do worse things. If I am standing, it is because You are supporting me.
“This brother does as much as he can. He is blind. How do You expect him to see without eyes? He is poor. How can You demand riches from him? Give him riches. Give him eyes to see“.
From “Monastic Wisdom” p. 77, available at Skete.com.
This affectionate prayer, this solidarity, it seems to me, is something missing from the reaction of the Pharisee in Jesus’s famous parable (Lk 18:9-14).
The following prayer was recommended by Elder Joseph to his spiritual child Photini, to say for herself; but given the way it is made in the third person, it seems to me one could easily adapt it for family members etc. too, in the spirit of what the Elder says above.
MY God, my God, look upon Thy Photini.
Open thy heavens once again, and let a drop of Thy divine grace fall.
Enlighten the eyes of her soul, and have mercy on her.
O my God! My God! Thou who seest the secret parts of our soul!
Sweeten our heart which the evil one has embittered and which has forgotten thy love.
“Monastic Wisdom” p. 282. (The female name “Photini” means “shining with light”.)