Paul’s prayer for Philemon in Phmn 6 is very interesting. It’s seldom translated well, however.
The new NIV is an improvement over the older rendering. The 1984 version made it seem that Paul was praying for Philemon to be a more effective evangelist: “I pray that you may be active in sharing your faith, so that you will have a full understanding of every good thing we have in Christ.”
The recent update has this: “I pray that your partnership with us in the faith may be effective in deepening your understanding of every good thing we share for the sake of Christ.”
The ESV leaves things a bit ambiguous, which isn’t necessarily wrong, in what Paul is praying for Philemon: “and I pray that the sharing of your faith may become effective for the full knowledge of every good thing that is in us for the sake of Christ.” Just what does “the sharing of your faith” mean? Is it Philemon’s sharing a common faith with Paul, Onesimus, and the other named Christians in the letter? Or, is it Philemon’s evangelistic practice?
I think the CEB also does a nice job with this verse: “I pray that your partnership in the faith might become effective by an understanding of all that is good among us in Christ.”
I would translate Paul’s prayer as follows: “I pray that the fellowship of your faith might become effective in the knowledge of all the good that is in us unto Christ.”
Paul emphasizes throughout the letter how everyone in the faith belongs to one another in the richest possible sense. He employs a number of rhetorical strategies to demonstrate this, not least the pervasive familial language. The named Christians in the letter are all brothers and sisters in Christ.
He stresses the belonging-to-one another character of our sharing in the faith.
Paul is praying that this reality would become actualized–that Philemon would fully recognize this reality and maximize it, living from it and making his decision in this matter with it in mind. That’s what he means by “fellowship of the faith,” or “partnership in faithfulness.”
This letter is a powerful instance of Paul’s ministry of “imagination transformation.” He leads his reader(s) into a compelling consideration of the faith so that their vision of all things is reshaped according to the gospel. He prays that they will see things anew, be renewed in how they conceive of all things, and live accordingly.