“Saint Paul rejoices in the same thing. If we had not rebuked you when correction by rebuke was possible, we would have harmed you. The loss would not have been yours alone, but ours also, because we would not have given you occasion for repentance.
“Do you see that failing to rebuke sinners harms both teacher and disciple? Therefore, he says, although I regretted it before I saw the fruit and benefit of the epistle, now I do not regret it. For the fruit was grief according to God.
“For grief over sins alone is profitable, and this is clear from what follows. One who grieves over the loss of wealth does not thereby repair the loss. One who grieves over the dead does not thereby raise him.
“One who grieves because of sickness not only is not delivered from the sickness, but even makes it worse. Only one who grieves over sins receives benefit from grief, because he exhausts and destroys sins.
“Grief is a medicine prepared for this one occasion. Here alone it has power and brings benefit. In other cases it causes harm. What is heavier than grief? Yet when it is grief according to God, it is far better than worldly joy.
“For that joy turns to nothing, while this grief works repentance unto salvation, not to be regretted. None of those who grieve with this grief has ever regretted it. Regret is especially characteristic of worldly grief.
“Blessed Paul, when speaking of the good fruits of grief according to God, had no need to bring outside examples to confirm what he said. He points to the Corinthians themselves and takes proofs from what they did.
“Thus, while praising them, he also instructs them and draws them still more to himself. ‘For behold this very thing, that you were grieved according to God, what earnestness it worked in you.’
“That is, look how your grief according to God made you concerned for yourselves. Such zeal and such very swift correction showed that they had been afraid.
“‘In everything you proved yourselves to be pure in the matter.’ This means not only that they themselves had not committed such a crime, but also that they did not indulge the one who had done it. They punished him and were indignant against him.
“The Apostle feared for the whole Church. He feared that the evil might spread and, going further, embrace the whole Church. Therefore he said, ‘A little leaven leavens the whole lump’ (1 Cor 5:6).
“Now, when they had corrected themselves, he expresses the same thing differently, saying, ‘that my care for you might be made manifest among you.’ That is, that you might see how I love you.
“Since I love you greatly, I feared that you might suffer harm from this scandalous example. I feared that you would be compelled to grieve on your own account.”
According to Theodoret’s explanation, “by the offender the Apostle means the one guilty of fornication, and by the offended, his father. For even after death he was offended by the dishonoring of his bed.”
Chrysostom says, “He lets them perceive that he feared for the whole Church. He feared that the evil might spread and, going further, embrace the whole Church” (cf. 1 Cor 5:6).