Colossians 4:9

With Onesimus, whom he adjoins to Tychicus. Some, because of his following commendation, think him to be another person different from the fugitive servant of Philemon; but the most, comparing the description here with the circumstances in the Epistle to Philemon, Colossians 4:10,16, &c., conclude him to be the very same, taking Philemon for a Colossian. A faithful and beloved brother, who is one of you; there, as here, being expressly called a beloved brother, yea, and, which may answer to faithful, Paul's spiritual son, who (whatever he had been) would be profitable and a benefit to Philemon, whom Paul would have to receive him as his own bowels. And that which might commend him to the Colossians was, that he was one of that city, or the same birth with themselves. They shall make known unto you all things which are done here; these two persons of credit (upon the apostle's testimony) in their different circumstances, might, as joint witnesses, give them a full and certain account how things went with the church, and particularly with Paul, now a prisoner at Rome.