5 On two accounts you see, or rather on three, correct judgement belongs not to us. One, because, though we be conscious to ourselves of nothing, still we need one to reprove our sins with strictness. Another, because the most part of the things which are done escape us and are concealed. And for a third besides these, because many things which are done by others seem to us indeed fair, but they come not of a right mind. Why do you say then, that no sin has been committed by this or that person? That such an one is better than such another? Seeing that this we are not to pronounce, not even concerning him who knows nothing against himself. For He who discerns secrets, He it is who with certainty judges. Behold, for example; I for my part know nothing against myself: yet neither so am I justified, that is, I am not quit of accounts to be given, nor of charges to be answered. For he does not say this, “I rank not among the righteous;” but “I am not pure from sin.” For elsewhere he says also, “He that has died is justified from sin,” that is, “is liberated.”
Again, many things we do, good indeed, but not of a right mind. For so we commend many, not from a wish to render them conspicuous, but to wound others by means of them. And the thing done indeed is right for the well-doer is praised; but the intention is corrupt: for it is done of a satanical purpose. For this one has often done, not rejoicing with his brother, but desiring to wound the other party.
Again, a man has committed a great error; some other person, wishing to supplant him, says that he has done nothing, and comforts him forsooth in his error by recurring to the common frailty of nature. But oftentimes he does this from no mind to sympathize, but to make him more easy in his faults.
Again, a man rebukes oftentimes not so much to reprove and admonish, as publicly to (ἐκπομπεῦσαι καὶ ἐκτραγωδῆσαι) display and exaggerate his neighbor's sin. Our counsels however themselves men do not know; but, “He that searches the hearts,” knows them perfectly; and He will bring all such things into view at that time. Wherefore he says, “Who will bring to light the secret things of darkness and make manifest the counsels of the hearts.”
Source: Homilies on First Corinthians (New Advent)