Philemon 1:20

Let me have joy of thee in the lord--In that thou doest what thou doest through the grace of Christ, through His dwelling in thee, and particularly thou imitatest Him in the breaking of bonds and freeing the captive.

(M. F. Sadler, M. A.)

Christ the true sphere of action

If Philemon receives his slave for Christ’s sake and in the strength of that communion with Christ which fits for all virtue, and so for this good deed a deed which is of too high and rare a strain of goodness for his unaided nature then “in Christ” he will be helpful to the apostle. In that case, the phrase expresses the element or sphere in which the act is done. But it may apply rather, or even also, to Paul, and then it expresses the element or sphere in which he is helped and refreshed. In communion with Jesus, taught and inspired by Him, the apostle is brought to such true and tender sympathy with the runaway that his heart is refreshed, as by a cup of cold water, by kindness shown to him. Such keen sympathy is as much beyond the reach of nature as Philemon’s kindness would be. Both are “in Christ.” (A. Maclaren, D. D.)

Provoked to virtue by a good example

Let me have profit of thee. There is here a play on the slave’s name, and the words are equivalent to, “Be thou to me an Onesimus.” He would extinguish the rising feeling of conscious merit and of boasting Philemon might entertain in compliance, and reminds him that by such compliance he would still be less helpful to him than had been Onesimus. He had Paul’s messenger, servant, fellow worshipper, and friend, and all he would have Philemon do was so to act as not to allow one of so despised a class to surpass him in generosity. It is good for men that are provoked to emulation by the Christian virtues of those around them. Their presence slays pride and inflames zeal, and invites to effort and to prayer, and makes it matter for shame even should slender abilities and advantages cast superior endowments into shade, should a Philemon be surpassed in Christian feeling and usefulness by an Onesimus. (R. Nisbet, D. D.)