As a result, Onesimus became a Christian, and Paul decided, with Onesimus’ consent, to send him back to Philemon. It was at this time, also, that Paul wrote letters to the congregations in Ephesus and Colossae. In both of these letters, he gave good counsel to Christian slaves and slave owners on how to conduct themselves properly in this relationship. (Eph. 6:5-9; Col. 3:22–4:1)

7. As regards Onesimus, how was Paul adhering to his high call as an apostle?

⁷ As is shown by this letter, Paul was not preaching a “social gospel,” trying to do away with the existing system of things and its institutions, such as slavery. He did not arbitrarily set even Christian slaves free, but, rather, he sent the runaway slave Onesimus on a journey taking him over 900 miles [1400 km] from Rome to Colossae, right back to his master Philemon. Thus Paul adhered to his high call as an apostle, abiding strictly by his divine commission of “preaching the kingdom of God . . . and teaching the things concerning the Lord Jesus Christ.”​—Acts 28:31; Philem. 8, 9.