"Paul is saying, 'I did regret before I saw the fruit and the gain. Now, however, I have no regret because of the great gain.' For such a thing is godly sorrow. Then he considers it, showing that sorrow is not in all cases a grievous thing, but only when it is worldly. And what is worldly? If you have sorrow because of money, reputation, over a deceased friend or relative, all these are worldly. Therefore, they also work death. For he that is in sorrow for reputation's sake feels envy and is sometimes driven to death. This was the sorrow that Cain sorrowed, and Esau. By this worldly sorrow Paul means the sorrow that harms those who sorrow.

 

"Only in respect to sin is sorrow a profitable thing. He who sorrows for loss of wealth does not repair that damage. He who sorrows for one who died raises not the dead to life again. He who sorrows over a sickness, not only is not made well but even aggravates the disease. He who sorrows over sin alone attains some advantage from his sorrow, for he makes his sins wane and disappear. For since the medicine has been prepared for sin, only in this case is it potent and displays its profitableness, but in the other cases it is even injurious. Yet someone may argue, 'Cain sorrowed because he was not accepted by God.' No, but rather because he saw his brother glorious in honor. For had Cain grieved because He was not accepted by God, it would have been right for him to emulate and rejoice with Abel. Instead, as it was, he grieved for his lack of glory, showing his worldly sorrow. Not so with David, nor Peter, nor any of the righteous. Therefore they were accepted, when they were grieving either over their own sins or those of others.

 

"What is more oppressive than sorrow? Still when it is godly, it is better than worldly joy. For worldly joy indeed ends in nothing; but godly sorrow 'works repentance unto salvation, a salvation that brings no regret.' For what is admirable in worldly sorrow is that one who had thus sorrowed would repent. This is an outstanding characteristic of worldly sorrow. For what is more regretted than a son who dies? And what is a heavier grief than a death of this sort? However, a father who at the height of his grief cares for no one and who wildly beats himself, after a time repents because he has grieved too extravagantly. He realizes that he has not benefitted himself, but, through it, even added to his affliction. But godly sorrow is not like this.

 

"Godly sorrow possesses two advantages, that of not being condemned in what a man grieves over, and that this sorrow ends in salvation. Both of these advantages are not present in worldly sorrow. Worldly sorrow is unto harm and after those who have sorrowed vehemently condemn themselves, they bring forth the greatest sign of having done it unto harm. But godly sorrow is the reverse [of this]. Therefore, Paul said, 'it leads to salvation without regret.' For no one will condemn himself if he has sorrowed for sin, if he has mourned and afflicted himself. Paul did not need to offer from other sources the proof of what he said, nor to bring forth those in the old histories who, sorrowed, but he offered the Corinthians themselves and furnished his proof from what they had done; that along with praises he might both instruct them and thus win them back to himself."

 

John Chrysostom, Homilies on 2 Corinthians, 15.2