Philemon 4–7 emphasizes the fellowship Christians have with one another due to their union with Christ, pointing explicitly to how Philemon’s love for the church benefited other believers (vv. 4–5, 7). But Paul does not only understand the benefits Philemon gave to other Christians as essential to his spiritual health, he also recognizes that Philemon had to receive blessings from others for his well-being.
Verse 6 is difficult to interpret, and there are many options as to what the apostle meant when he wrote it. Most of these options, however, are nuanced ways of saying the same thing. Basically, “sharing of your faith” refers to the fellowship in Jesus that all believers have with one another. Paul’s hope for Philemon was that this shared fellowship would help him understand what was an oblique request for the freeing of his slave Onesimus and enable him to respond rightly to the apostle’s appeal.
To put it another way, verse 6 is Paul’s reminder to Philemon that he and the other Christians in Colossae shared a bond that had to be considered when making the decision itself and in relation to the effects that freeing Onesimus might have on the church. The covenant community has something to say about “private” matters, and every private moral decision we make impacts the body of Christ, particularly when these decisions cannot help but be made public (Ruth 4; 1 Cor. 5). It is false to say ethical decisions &mdamdash; whether about marriage or money, for example — are none of the church’s business. No Christian, of course, may bind us where Scripture leaves us free, but we fool ourselves if we believe our choices are uninfluenced by other believers or have no ramifications for God’s people.
Freeing Onesimus was no easy matter for Philemon. He would likely lose esteem in the community for freeing a runaway slave and might need the help of the church to sustain or improve his reputation. Philemon required “exceptional faith, love, and knowledge,” as one commentator notes, to do the right thing. The fellowship of believers in the church, understanding their unity in Christ and the ways Scripture called them to treat one another by the power of the Spirit, could help Philemon see that the apostle’s request for Onesimus’ release was good and proper, and Paul prays in verse 6 that Philemon would indeed heed this collective wisdom.