Along with Paul’s letter to Philemon, Paul sent a letter to the other believers in the same city: Colossae. Paul asked Tychicus to deliver the letter, with the help of the escaped slave Onesimus, whose master, Philemon, had been asked to accept him on back on equal terms, as a brother:
Colossians 4:9 I am also sending Onesimus, a faithful and beloved brother, one of your own people. He and Tychicus will tell you everything that’s happening here.
Paul wrote this immediately after reminding slaves and master how they should behave towards each other:
Colossians 3:22-24 Slaves, obey your earthly masters in everything you do … Remember that the Lord will give you an inheritance as your reward, and that the Master you are serving is Christ.
Colossians 4:1 Masters, be just and fair to your slaves. Remember that you also have a Master—in heaven.
AIt would have had to have put the pressure on Philemon to welcome Onesimus as he would welcome Paul: as a brother and partner in Christ. Not only did Philemon have the original request (from the letter to him), but now the whole church in Colossae was told this slave was ‘one of your own’.
It also made Onesimus’ relationship with Philemon clear. Yes, he was still a slave, and he had to do what the boss said (don’t we all?), but he was no longer a non-person. He was a brother.