The following is from Dennis Hamm’s forthcoming commentary on Philippians, Colossians, and Philemon (November 2013), commenting on Philemon 10-11:
I rather urge you out of love.
Rather than pull rank Paul elects to lean on his relationship with Philemon as a fellow Christian. But he also enlists the emotional appeal of his condition as a prisoner for (literally, “of “) Christ Jesus, repeating what he said in verse 1. His characterization of himself as an old man underscores the indignity of his confinement, and possibly his seniority over Philemon. “Old man” evokes for us twenty-first-century Western readers someone in his eighties or nineties, but scholars note that in the Greco-Roman world the word presbytēs could refer to someone between fifty and fifty-six years of age.
At last Paul introduces the name of the person who will be the subject of his request—Onesimus. The original addressees would have recognized the name of a member of Philemon’s household. Even those who did not know the man would have recognized the name, which means “useful,” as a common slave moniker. It is much like the name Onesiphorus (2 Tim 1:16; 4:19), which means “profit-bearing.” Paul describes Onesimus as my child . . . whose father I have become in my imprisonment (or “while I was in chains,” NIV). Having heard Paul describe his relationships with fellow Christians with similar metaphors in verses 1–2—”brother,” “sister,” “fellow soldier”—we are not surprised to hear “my child” and “whose father I have become” as another figure of speech. Indeed, Paul speaks elsewhere in his letters of his paternal role in the new birth of Christian conversion. A good example is 1 Cor 4:15: “Even if you should have countless guides to Christ, yet you do not have many fathers, for I became your father in Christ Jesus through the gospel.”
This Christian conversion of the slave Onesimus has wonderful implications, which Paul proceeds to describe in a marvelous bit of wordplay, when he refers to Onesimus as the one who was once useless (achrēston) to you but is now useful (euchrēston) to [both] you and me. There are two kinds of wordplay here. First, Paul alludes to the literal meaning of the name: Your man Useful became quite useless to you while absent from your household; but now I’m sending him back to you as truly useful. Second, those who heard the letter read aloud would have noticed a pun in the contrast between a-chrēston and eu-chrēston. For these words can sound like a-Christon and eu-Christon, which can be heard as “not-Christ-ed” and “well-Christ-ed”; that is, Onesimus was previously without Christ, but now he has become a Christian.