1 Timothy 6:1,2

There were millions of slaves in the Roman empire at the time Paul wrote this letter. Those converted to Christ were urged to be good servants giving proper respect to their masters. If they were offered their freedom, they should certainly take it and only be a slave to the Lord (1 Corinthians 7:21-24). If they remained in a man's service, they should submit to their masters as to the Lord (Colossians 3:22-24). Some might think of making their work look good on the surface while in reality doing a half-hearted job, but Christians serve the Lord in everything they do (1 Timothy 6:1; Ephesians 6:5-8).

It was possible for a Christian to be a master of slaves, as in the case of Philemon (Philemon 1:8-16). Further, he might have slaves who became Christians, as in the case of Onesimus. Such slaves might reason that we are all one in Christ and there is neither bond nor free (Galatians 3:28). In the spiritual sense, they would have been correct, but spiritual relations do not change physical relations entirely. Wives must still be subject to their own husbands and slaves must be subject to their masters. Now, as Paul went on to say, it should be a greater joy to work under someone and benefit them through your service because a fellow Christian, brother, receives the good from the work you perform (1 Timothy 6:2).