Paul says that if Onesimus “has wronged you at all, or owes you anything,” it should be charged to Paul. He adds, “I will repay it,” writing it with his own hand (Philemon 1:18–19).
Paul asks Philemon to treat Onesimus as Paul’s own representative: if Philemon counts Paul a true partner, he should welcome Onesimus the way he would welcome Paul (Philemon 1:17). If Onesimus has caused any loss or debt, Paul tells Philemon to charge it to Paul’s account, promising repayment. These verses sit in the center of Paul’s appeal about Onesimus and explain the practical outcome Paul wants. Just before this, Paul reframes Onesimus as more than a servant—someone now bound to Philemon in a new, close relationship (see Philemon 1:15–16).
Paul builds his request on shared relationship: if Philemon counts Paul a true partner, he should welcome Onesimus the way he would welcome Paul (Philemon 1:17). The text claims Paul is willing to take personal responsibility for any harm or debt Onesimus caused, telling Philemon to put it on Paul’s account and promising repayment (verses 18–19).
A careful answer keeps the immediate passage, the book's argument, and the whole-Bible storyline together, so the question is answered in context instead of as a detached idea.
Start with Philemon 1:18-19, then read the surrounding section so the answer stays connected to the passage's flow.
18But if he has wronged you at all, or owes you anything, put that to my account.
19I, Paul, write this with my own hand: I will repay it (not to mention to you that you owe to me even your own self besides).