Paul's final letter is a very short one to a guy named Philemon who's slave had run away. The slave, Onesimus, had run into Paul (perhaps in prison?) and Paul had converted him to Christianty. In that time, slaves who ran away could be punished by death, but Paul suggests that Philemon not kill his slave who has returned but have mercy on him and accept him as a brother in Christ.
Since we don't know how Philemon received the letter, I guess we don't know if Onesimus is saved, but I think it's a good guess to say he was accepted as a fellow Christian and not punished. A nice little tale of forgiveness and conversion.