"I appeal to you for my child Onesimus, whom I have begotten in my imprisonment, who formerly was useless to you, but now is useful both to you and to me. I have sent him back to you in person, that is, sending my very heart, whom I wished to keep with me, so that on your behalf he might minister to me in my imprisonment for the gospel; but without your consent I did not want to do anything, so that your goodness would not be, in effect, by compulsion but of your own free will. For perhaps he was for this reason separated from you for a while, that you would have him back forever, no longer as a slave, but more than a slave, a beloved brother, especially to me, but how much more to you, both in the flesh and in the Lord." (Philemon 10-16)We don't know much about Onesimus other than his name means "Useful" which helps us to understand Paul's reference to Onesimus being previously useless to Philemon but now useful to himself. We also run across another Onesimus later at Ephesus, whom Ignatius speaks well of when he writes, "I received, therefore, your whole multitude in the name of God, through Onesimus, a man of inexpressible love, and your bishop in the flesh, whom I pray you by Jesus Christ to love, and that you would all seek to be like him." (Ignatius, Letter to the Ephesians, Chapter 1) While there is no direct evidence that this is the same Onesimus from Paul's letter, if he did return to Paul and became part of his team, he could have traveled to Ephesus with Timothy who was there when Paul penned his two letters to him. Also, Onesimus could easily still have been alive when Ignatius met him and reported his commendations of him. The only other thing we know about Onesimus is that he was a slave, and a runaway slave at that.
We know a bit more about Philemon. We know he as a believer and dear to Paul. We also know that he hosted the church in his house. He was a man of great faith and love, and that he cared deeply for his brothers and sisters in Christ. He was also a slave owner. It can be hard for us today to imagine a believer owning slaves, yet it was not too long ago, in our own culture, when such things happened and, in the Roman era, slavery was pervasive and common place. In the Roman Empire there were more slaves than freemen, some owning in excess of 20,000 salves each. Some bought their slaves, some inherited them, and some had none, but no one was without exposure to slavery and its effects in their daily lives.
The gospel does not call for the immediate end of slavery nor for the summary release of all slaves, even by believers. That is not to say that the gospel condones slavery or is indifferent to its suffering. Years later it would be those whose minds were transformed by the evangelical word who would fight hard for the abolition of slavery. However, slavery existed and believers were forced to live by faith in a slave society; the gospel compelling them to treat all people as equals, whether slaves or free, and to love one another, whether slaves or free. It was through the gospel that all men were made equal, all being salves of sin, and all being offered freedom through Christ.
It is hard for us to imagine what we would do if we were in Paul's shoes (or sandals) and it may even be tempting to judge Philemon for his possession of slaves, but to do so would be to miss the whole point of this letter. What is of keen interest in this letter to us is the need for our commitment to doing what's right and to upholding a reputation as one who always does what is right. Paul was committed to doing what was right, even if it was contrary to his desires, whats, and wishes. He wished to keep Onesimus with him but his wants had to take second place to what was right and proper. Similarly, he knew he could trust sending Onesimus back to Philemon because Philemon was a good man and one also committed to what was right. Paul had confidence that Philemon would do the right thing. Oh, that the same might be said about us as well.