Onesimus, was a slave of a Colossian believer named Philemon, he had run away from his master and somehow ended up meeting Paul.
In an amazing display of the power of the gospel to change lives, Onesimus apparently became a believer and agreed to return to Philemon to face whatever consequences awaited him.
At the same time, Paul sent a letter (now known as the New Testament book of Philemon) with him telling Philemon of how useful Onesimus, whose name means “useful,” had become to him. In the letter, Paul urged Philemon to welcome Onesimus back as a brother rather than a slave. Paul even asked Philemon to charge to him any debt incurred by Onesimus, although Paul was quick to point out that Philemon owed his very self to Paul—most likely meaning that Paul had led Philemon to Christ.
And just in case Philemon needed some extra encouragement, Paul asked him to prepare a guest room in case he happened to stop as he passed through Colosse! Surely the thought of physically looking Paul in the eye was all the motivation he needed to do the right thing.
The question remains: Who are you going to serve? If you had asked Onesimus before he became a believer, he may have bitterly answered, “Philemon,” or perhaps after he fled, “No one but myself.” But in the end, we all serve somebody else—either the Lord or the devil. After Onesimus became a believer, he went back to Philemon perhaps expecting to return to a life of servitude, but really he was serving the Lord. Who are you going to serve?