Philemon 1:10-13

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. 12I am sending him—who is my very heart—back to you. 13I would have liked to keep him with me so that he could take your place in helping me while I am in chains for the gospel.