“I have sent him (who is my very heart) back to you. I wanted to keep him with me so that he could serve me in your place during my imprisonment for the sake of the gospel. However, without your consent I did not want to do anything, so that your good deed would not be out of compulsion, but from your own willingness. For perhaps it was for this reason that he was separated from you for a little while, so that you would have him back eternally, no longer as a slave, but more than a slave, as a dear brother. He is especially so to me, and even more so to you now, both humanly speaking and in the Lord. Therefore if you regard me as a partner, accept him as you would me.”
Having said that Onesimus is now living up to his name, Paul sends him back to Philemon. Can you imagine the tension of their meeting: runaway slave returns to face former master. Runaway slaves were treated with utter contempt and faced torture and possible death. Here’s Paul, then, saying that Onesimus is on his way back and is to be received as you would me.
Onesimus has been ministering to Paul during [his] imprisonment for the sake of the gospel and Paul would have loved him to stay. However, he knows that God has bigger plans and that perhaps he had met Onesimus in order that he return to Philemon to right the wrongs of the runaway. Caring deeply for this dear brother, Paul wants Philemon to accept him as you would me.
The same is true for you and for me. In our fallen and fallible selves, we had run away from God (Colossians 1.21). Then, through the work of a single intermediary, a single person between God and ourselves, we have been reconciled and accepted as more than runaway sinners, but as children of God (Romans 5.10, Colossians 1.22, 1 Timothy 2.5, 1 John 3.1).
As Paul did for Onesimus, Jesus did for you.
“…accept him as you would me.”
His sacrifice on the cross was one that we owed (Romans 6.23) but through it we are accepted as He is (2 Corinthians 5.21, 1 Peter 3.18, Isaiah 53.5).