Philemon is a very short letter written by Paul while he was in prison. He met a slave there named Onesimus, who is the subject of the letter. Paul is asking Philemon to accept Onesimus back and forgive any wrongdoings the slave may have committed. The two obviously had a pretty close relationship, in fact Paul refers to himself as a father figure to the younger man (Philemon 10). It’s likely that the reason Paul grew so attached to Onesimus is because they share the same religious views, and that’s why Paul wants him to return to his city. Perhaps he sees Onesimus as someone who can continue to spread the gospel to others, but not if he’s imprisoned.

Philemon himself likely had a lot of power and influence if Paul is writing directly to him to ask for this favor. He obviously was pretty wealthy, because he owned slaves, and he likely had a lot of religious influence as well. Their relationship seems to be friendly based on this letter, but it’s very obvious that Paul is pressuring Philemon into doing what he wants, in a very polite way. One of the most powerful parts of the letter comes at Philemon 21, where Paul says that he is writing to him “knowing that you will do even more than I say”. He follows that up in the very next sentence with an announcement that he will be coming to visit soon. The implied message here being that Philemon needs to take back Onesimus, and do it before Paul returns. Given that the entire town would have heard this message, it seems like Philemon would have been under a lot of pressure to do what Paul asked, regardless of his own feelings on the matter.