2 Corinthians 7:8

7:8 For even if I made you sad by my letter, I do not regret having written it (even though I did regret it, for I see that my letter made you sad, though only for a short time).

2 Corinthians 7:10

7:10 For sadness as intended by God produces a repentance that leads to salvation, leaving no regret, but worldly sadness brings about death.