2 Corinthians 7:8-9

I am not sorry that I sent that severe letter to you, though I was sorry at first, for I know it was painful to you for a little while. Now I am glad I sent it, not because it hurt you, but because the pain caused you to repent and change your ways. It was the kind of sorrow God wants his people to have, so you were not harmed by us in any way.