Paul, a prisoner of Christ Jesus, and Timothy our brother, To our beloved coworker Philemon, to our sister Apphia, to our fellow soldier Archippus, and to the church in your house: Grace to you and peace from God our Father and the Lord Jesus Christ (Philemon 1-3).
It must not be missed that this letter is addressed to the church in Philemon’s house. It may seem strange to modern Western minds that Paul seems to be making the relationship between Philemon and Onesimus a public matter. In the twenty-first century we are so imbued in a hyper individualistic context that it's hard for us to understand why such matters should not be private. It is important to realize that Paul and his contemporaries did not have such an individualistic notion of privacy that we do today. To be sure, they understood that there were matters of a personal nature, but they rightly knew that even personal matters could affect the larger community.