Paul calls Philemon “our beloved fellow worker.” He also refers to him as a “partner” when he asks him to receive Onesimus as he would receive Paul (Philemon 1:1; Philemon 1:17).
In Philemon 1:1–3, Paul opens by identifying himself as a prisoner connected with Jesus Christ and by including Timothy as a co-sender. He addresses not only Philemon but also Apphia, Archippus, and the gathering that meets in Philemon’s home, widening the audience beyond one person. These verses are the letter’s opening greeting, establishing who is writing, to whom, and with what tone. Paul foregrounds his situation as a prisoner, which can make the reader expect an appeal that leans on relationship and sympathy rather than authority.
Paul opens by naming himself and Timothy, then naming the recipients (Philemon, Apphia, Archippus, and the gathering that meets in the home). The text’s explicit claim is that this letter is not addressed to Philemon alone; it is framed to be heard by a household-based community (verse 2).
A careful answer keeps the immediate passage, the book's argument, and the whole-Bible storyline together, so the question is answered in context instead of as a detached idea.
Start with Philemon 1:1, then read the surrounding section so the answer stays connected to the passage's flow.
1Paul, a prisoner of Christ Jesus, and Timothy our brother, to Philemon, our beloved fellow worker,