I appeal to you for my son Onesimus, who became my son while I was in chains. (Philemon 1:10)
In the Epistle to Philemon, Paul is writing on behalf of Philemon's runaway slave, Onesimus. He asks Philemon to forgive Onesimus and take him back. But does Paul have a hidden agenda?
Formerly he was useless to you, but now he has become useful both to you and to me. (Philemon 1:11)
Onesimus means "useful." Paul is engaging in a bit of wordplay here. Notice that Onesimus is useful not only to Philemon, but also to Paul.
I am sending him—who is my very heart—back to you. I would have liked to keep him with me so that he could take your place in helping me while I am in chains for the gospel. But I did not want to do anything without your consent, so that any favor you do would not seem forced but would be voluntary. (Philemon 1:12-14)
Now we see what's in it for Paul. Paul wants Philemon to give him his slave. Paul seems to be saying, "Hey I could just take him, but I'll give him back to you, so that when you give him to me it will seem voluntary." Talk about coveting your neighbor's manservant! Doesn't Paul realize he's breaking the Tenth Commandment here?
Philemon is traditionally dated between 50-60 AD, although there's no reference to it until about hundred years later. The epistle is first mentioned by Tertullian, (c. 160 – c. 220 AD) who said it was included in Marcion's canon (c. 130 AD). The earliest known manuscript of the Epistle to Philemon is Papyrus 87 which has been dated to the late 2nd or early 3rd century based on hand writing analysis. The traditional dating of 50-60 AD is based on the assumption that the events described in Acts are genuinely historical. However, no Christian had access to any of Paul's letters before the gnostic Marcion. When we consider that all of Paul's letters appear at the same time in a single collection, it's quite likely that Marcion wrote the letters of Paul. All available evidence indicates that Philemon, including all of Paul's epistles, were written in the second century and the historical Paul may actually have been Marcion.