4. The Parts are the Introduction, the treatment, and the Epilogue. Interpreters of the Epistle, Ancient, Reformed, Lutheran, Roman Catholic; and also a Synoptic Table.
The Epistle has three parts: an introduction, the treatment, and an epilogue.
I. The Introduction.
For Philemon, Apphia, and Archippus, he prays grace and peace (verses 1-3).
II. The Treatment.
Giving thanks to God on account proven faith and charity of Philemon (verses 4-9), by several argument he intercedes for the reception of Onesimus (verses 10-21).
III. The Epilogue.
Ordering that hospitality be prepared for him (verse 22), he sends greeting and closes (verses 23-25).
A New Testament Survey! https://www.fromreformationtoreformation.com/blog/categories/heidegger-nt-handbook