John Chrysostom
He had been sent by the Colossians (Col 1:7; Col 4:12), so from this it is clear that Philemon lived in Colossae.
Paul calls him “my fellow prisoner,” expressing that he too was in great affliction.
Thus, if not for the Apostle himself, then for this man the request ought to be heard.
The one who is in affliction, and who has left his own affairs to care for others, ought to be heard.
On the other hand, the Apostle here reproves Philemon in case he should not show mercy to his own slave.
For his fellow citizen became Paul’s “fellow prisoner” and suffers together with him.
And he adds further: a fellow prisoner with me for Christ Jesus, that is, for Christ.