St. John Chrysostom had very strong words for Christians who want to convert 
others to Christ or who want to confront a Christian who has fallen into sin.
“Do not trample, but admonish. Do not revile, but advise. Do not assail with pride, but correct with tenderness. These commandments offer great blessings to the obedient, but great evil for those who ignore them.
‘All right,’ you say, ‘if one commits fornication, may I not say that fornication is a bad thing and correct the person who fornicates?’ Yes, correct him – but as a physician providing medicines, not as an adversary exacting a penalty. Be not bitter in pronouncing sentence.
If you judge your brother, be sure to judge yourself first. Care about the one you judge, and judge him not for things you yourself are guilty of.” (Homily on “Judge not, that you be not judged”, p. 3)
Fraternized 