If he has done you any wrong or owes you anything, charge it to me.
Two Bible studies on Philemon. Just two because it’s not a very long book and they’re sort of in the wrong order and the first looks at the events behind the letter (verses 12-25 mostly) and the second is a study on 1-11. The reason for this is that the first looks at how Paul and Philemon are putting the gospel into practice and thinks of some ways we can too; the second is focused more specifically on how that works out in relationships between believers.
Philemon – The Gospel in action
and a powerpoint to go with it, telling the story and if you view the notes providing helpful wording that makes it more obvious how it fits what Christ has done: Philemon Overview