For even when we came into Macedonia our flesh had no rest, but we were afflicted on every side: conflicts without, fears within. But God, who comforts the depressed, comforted us by the coming of Titus; and not only by his coming, but also by the comfort with which he was comforted in you, as he reported to us your longing, your mourning, your zeal for me; so that I rejoiced even more. 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.
2 Corinthians 7:5-10 NASB