Colossians seems to be the key now. I've always dismissed it but now I want to take a fresh look at it. For example, the Wikipedia page notes that:
Colossians has some close parallels with the letter to Philemon: names of some of the same people (e.g., Timothy, Aristarchus, Archippus, Mark, Epaphras, Luke, Onesimus, and Demas) appear in both epistles, and both are claimed to be written by Paul.
I noticed this too as I was re-reading it. And I've never had any issue with Philemon being genuine (though I suppose I should take a closer look at counter arguments).
But there's also the fact that Marcion is said to have used it (along with Philemon). Here is how Epiphanius puts it:
This is Marcion’s corrupt compilation, containing a version and form of the Gospel according to Luke, and an incomplete one of the apostle Paul — not of all his epistles but simply of Romans, Ephesians, Colossians, Laodiceans, Galatians, First and Second Corinthians, First and Second Thessalonians, Philemon and Philippians. (There is no version) of First and Second Timothy, Titus, and Hebrews <in his scripture at all, and> even the epistles that are there <have been mutilated>, since they are not all there but are counterfeits. And <I found> that this compilation had been tampered with throughout, and had supplemental material added in certain passages — not for any use, but for inferior, harmful strange sayings against the sound faith, <fictitious> creatures of Marcion’s cracked brain.
https://sites.google.com/site/inglisonm ... postolicon
So it was early enough for Marcion and others to accept it as Pauline, and given that the same people are mentioned in it and Philemon, I'm starting to lean towards the idea that if it wasn't written by Paul it could have been written by someone who knew him. And an obvious candidate would be Timothy, given that the letter begins, "Paul, an apostle of Christ Jesus by the will of God,
and Timothy our brother, to the saints and faithful brothers in Christ at Colossae."
And if
this is the case, perhaps there could be something to the detail in 4:14 that Luke was a physician. However, somewhere along the line I picked up that Marcon's Colossians didn't have this detail, and that complicates things.
But if that is the case then the question would be, why was it added? It makes sense that it would be
deleted by Marcion given his disdain for the body (as per Docetism according to whoever I picked up this detail from), but why would an orthodox writer
add it? Does that tiny detail really derail Docetism? It seems simpler to me to suppose that someone who knew Luke (Timothy?) knew this detail about him.