In addition to illustrating Paul’s rhetoric of persuasion, Philemon, his smallest letter, provides a case study of what life in Christ, in Christ-communities which were the new creation, was to be like. The issue was larger than resolving a conflict between Philemon, the master, and Onesimus, the slave. It was whether   slavery was acceptable within life in Christ. Philemon was a Christ-follower who had slaves. Onesimus became a Christ-follower – he was in Christ. Thus the issue is: May a Christian have a slave who has become a Christian.

Paul’s answer is no. A Christian master may not have a Christian slave. That this larger claim underlies his appeal to Philemon is apparent from the language he uses. Receive Onesimus back as “a beloved brother.” That is “new family” language again. And the two are to be brothers “both in the flesh and in the Lord” – indicating not just spiritual equality but equality in the flesh.

It is interesting from our perspective in the 21st Century. We would say that   slavery is wrong whether or not the slave is a Christian. In Paul’s society they had not yet come to that conclusion.

This letter is a concrete application of what Paul wrote about life in Christ in Galatians. If you have been baptized into Christ and clothed yourselves with Christ, there is no longer Jew or Gentile, slave or free, male or female, for all of you are one in Christ Jesus. Life in Christ abolishes the hierarchical relations of conventional culture. Its quality is not only spiritual, but also in the flesh.

We do not know how Philemon acted in response to Paul’s appeal. Did he free Onesimus immediately? Did he grumble and maybe even resist for a while? Though we do not know, early Christian tradition reports that Onesimus eventually became a bishop in Ephesus. He was at some point freed – and this letter may be in the New Testament because of him.

So we see that even one of the primary apostles of Christ did not fully understand the teaching of Jesus, which we now believe insists that all humans are created equal because they share in the same God life-force and, therefore, one cannot be the master over the other.

Many ancient biblical commentators wondered why an ostensibly private letter with little pastoral concern should have been inspired. The fact that it is creates a problem for the social character of inspiration. Paul does not invoke his apostolic authority to demand obedience of Philemon. He writes rather as a prisoner, an old man, and confronts Philemon with a plea of love. Paul did not try to change the existing social structure. Modern Christian thinking is repelled by the idea of slavery. Remember that this outlook is a development and refinement of principles advocated by Paul.