SAINT PAUL WAS SERVING one of his periodic sentences behind bars when he met Onesimus. Onesimus was a slave who belonged to a Christian friend named Philemon, and why he was in jail nobody knows. Maybe he was a runaway. Maybe Philemon had charged him with theft. Anyway, when Onesimus had done his stretch and was about to be sprung, Paul wrote a short letter for him to give to his master, Philemon, when he got back home.
While they were doing time together, Paul wrote, not only had he made a Christian out of Onesimus, but he had also made him one of his best friends. The boy was like a son to him, Paul said, and sending him back was like "sending my very heart" (Philemon 1:12). Onesimus means "useful," and Paul plays on the name by saying he's become so useful to him that he doesn't know what he'll do without him. He doesn't come right out and say what he wants Philemon to do, but the hint could hardly be broader. "I would have been glad to keep him with me in order that he might serve me on your behalf during my imprisonment for the gospel," he wrote, "but I preferred to do nothing without your consent." In case that wasn't enough, he added, "Yes, my brother, I want some benefit from you in the Lord. Refresh my heart in Christ." In the meanwhile he hopes that Philemon will receive the boy back "no longer as a slave but more . . . as a beloved brother" (1:13-20).
It's not known whether or not Philemon took the hint and let Onesimus return to be the old saint's comfort for what time was left him, but there's at least one good reason for believing that such was the case. Years later, when Paul was long since dead, another saint by the name of Ignatius was in jail. The bishop of Ephesus had sent some friends to visit him, and Ignatius wrote asking if a couple of them could be allowed to stay. Ignatius in his letter used some of the same language that Paul had used in his to Philemon, almost as if he was trying to remind him of something. And what was the name of the bishop he wrote to? It was Onesimus.
There's no proof that he was the same slave boy grown old and venerable with a mitre on his head, but it's very tempting to believe so. If he was, then he refreshed the hearts of not just one old saint, but two, and was more true to his name, useful, than Paul ever lived to discover.