2 Corinthians 7:8-9

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.