2 Corinthians 7:8-10

For though I caused you sorrow by my letter, I do not regret it; though I did regret it—for I see that that letter caused you sorrow, though only for a while— I now rejoice, not that you were made sorrowful, but that you were made sorrowful to the point of repentance; for you were made sorrowful according to the will of God, so that you might not suffer loss in anything through us. For the sorrow that is according to the will of God produces a repentance without regret, leading to salvation, but the sorrow of the world produces death.