15 For perhaps he was separated. If we are angry on account of offenses committed by men, our minds ought to be soothed, when we perceive that those things which were done through malice have been turned to a different end by the purpose of God. A joyful result may be regarded as a remedy for evils, which is held out to us by the hand of God for blotting out offenses. Thus Joseph — when he takes into consideration, that the wonderful providence of God brought it about, that, though he was sold as a slave, yet he was elevated to that high rank, from which he could provide food for his brethren and his father — forgets the treachery and cruelty of his brethren, and says, that he was sent before on their account. (Genesis 45:5.)
Paul therefore reminds Philemon that he ought not to be so greatly offended at the flight of his slave, for it was the cause of a benefit not to be regretted. So long as Onesimus was at heart a runaway, Philemon, though he had him in his house, did not actually enjoy him as his property; for he was wicked and unfaithful, and could not be of real advantage. He says, therefore, that he was a wanderer for a little time, that, by changing his place, he might be converted and become a new man. And he prudently softens everything, by calling the flight a departure, and adding, that it was only for a time.
That thou mightest receive him for ever. Lastly, he contrasts the perpetuity of the advantage with the short duration of the loss.