Charles Ellicott Commentary Philemon 1:20

"Yea, brother, let me have joy of thee in the Lord: refresh my heart in Christ." — Philemon 1:20 (ASV)

Let me have joy of you.—Properly, may I have pleasure, or profit, from you: a phrase used especially concerning the mingled pleasure and help derived from children. (See Dr. Lightfoot’s Note on this passage.)

The word “I” is emphatic. St. Paul puts himself forward to plead for Onesimus, what he himself could not plead. Nor can it be accidental that the word “profit” is the root of the name Onesimus. St. Paul says, in effect, “May I find you (as I have found him) a true Onesimus.”