ACC ~ Philemon 1 v19

SPIRITUAL GRACE. CHRYSOSTOM: Paul writes at once movingly and with subtle spiritual grace. The idea is that since Paul did not refuse to extend his credit, [how ironic it would be] if Philemon should refuse to receive Onesimus! The mention of this deserved favor would both shame Philemon into compliance and bring Onesimus out of trouble. HOMILIES ON PHILEMON 3.

THEODORE OF MOPSUESTIA: Paul says, “I make this promise to you, since you yourself see the abundant rewards that God’s mercy has in store when you exercise goodness toward Onesimus. You ought to think on these things in the light of what you owe to me, though I ought not to refer to it.” COMMENTARY ON PHILEMON.