Philemon 1:9-11

9yet I prefer to appeal to you on the basis of love. It is as none other than Paul—an old man and now also a prisoner of Christ Jesus— 10that I appeal to you for my son Onesimus, Onesimus means useful. who became my son while I was in chains.

11Formerly he was useless to you, but now he has become useful both to you and to me.