Philemon ends on a cliffhanger. Does Philemon forgive and free his former slave? Is Onesimus forced to return to slavery, or worse, sentenced to death? What happens to Onesimus?
Scripture doesn’t give us the answer to those questions. Outside of Philemon and the end of Colossians, Onesimus isn’t mentioned anywhere else in the New Testament. Most scholars believe that the simple fact that we have the letter suggests that Philemon did the right thing - after all, it doesn’t seem likely that Philemon would have wanted it preserved if he had Onesimus beaten and returned to his chains.
There is one text that might shed some light on Onesimus’ fate. Ignatius of Antioch - an early church father and student of John - wrote a letter to the church in Ephesus as he was being transported to Rome for execution. In it he writes:
“I hope, indeed, by your prayers to have the good fortune to fight with wild beasts in Rome, so that by doing this I can be a real disciple. In God’s name, therefore, I received your large congregation in the person of Onesimus, your bishop in this world, a man whose love is beyond words. My prayer is that you should love him in the spirit of Jesus Christ and all be like him. Blessed is He who let you have such a bishop.” (Ignatius' Epistle to the Ephesians, emphasis mine)
While we don’t know for sure if the Onesimus in Ignatius’ letter is the same person, there are several signs that he might be. For one, the timing is right (Ignatius was writing about 40 years after Paul). Ephesus is also in Asia Minor - the same region as Colossae, where both Philemon and Onesimus are from. If so, it makes for an inspiring and fitting end to this tale - and a reminder of the power of grace to transform lives.