So if we meet, and I biff you on the head, it's because God wanted me to. (Rightfully deserved?) These are two men dealing with each other. The question at hand does NOT rise up to the level of God. Paul wants to keep Onesimus. God has determined that Paul would instead send Onesimus back to Philemon, so if Philemon wishes for Onesimus to serve Paul, it will be Philemon's choice. Now, how that rises to the level of God deciding you will pick your nose with your left pinky, instead of your right index finger...I don't know. Perhaps you can explain that to us? This has nothing to do with libertarian free will, because God may have determined that this happen. You have yet to prove that God does not determine anything, while we know that there is scripture that clearly states God determined. And the passage being dealt with is "
14 and apart from thy mind I willed to do nothing, that as of necessity thy good deed may not be, but of willingness, 15 for perhaps because of this he did depart for an hour, that age-duringly thou mayest have him, 16 no more as a servant, but above a servant -- a brother beloved, especially to me, and how much more to thee, both in the flesh and in the Lord!" (YLT) So even Paul is saying that perhaps the reason God is having Paul send Onesimus back is so that Philemon and Onesimus can be reunited, not simply as master and servant, but as so much more. Also, I notice free will isn't mentioned here in the literal translation of the greek.