Formerly he was useless to you, but now he has become useful both to you and to me.Philemon 1:11 NIV
Onesimus was a slave who had run away. Somehow he had then encountered Paul while he was in prison. The encounter was life-changing for Onesimus. He came to know the Lord and was helpful to Paul during his imprisonment. But there remained a problem. By Roman law, Onesimus belonged to Philemon. In addition, Onesimus and Philemon were now both believers, but there was a ruptured relationship between them that needed to be dealt with. So Paul sent Onesimus back to Philemon with this letter to deal with both of these issues.
In this letter, Paul made a play on Onesimus’ name. A name that meant “useful.” As a runaway slave, Onesimus had been useless to Philemon. But he had become useful to Paul. He would also be useful now to Philemon as a fellow believer. In this letter, Paul urged Philemon to give Onesimus his freedom. But whether he did or not, Onesimus will now be useful to Philemon.
It strikes me that Onesimus’ story should be that of every believer. We were slaves to sin and useless to God. But he has freed us from that slavery and brought us into his family. And now, rather than being useless, we have become useful members of the kingdom of God. So, serve the Lord, and his people, with joy and thankfulness for what he has done in your life.