Note 9 at Col. 4:14: Luke was the author of the Gospel of Luke and also the book of Acts. According to tradition Luke was one of the 70 that the Lord commissioned to go out and preach the gospel of the kingdom (Lk. 10:1). Since Paul mentioned Aristarchus, Mark, and Justus as being Jews, Luke was probably a Gentile.

Note 10 at Col. 4:14: Some have taken this mention of Luke as "the beloved physician" to indicate that Luke was still practicing medicine. It has even been said that Luke ministered right alongside the Apostle Paul. Paul would pray for God to heal them supernaturally and if that didn't work, then Luke would treat them medically. There is no evidence, scriptural or otherwise, which indicates that this ever happened. On the contrary, since Luke wrote the book of Acts (see AUTHORSHIP in the INTRODUCTION TO THE ACTS OF THE APOSTLES, p. 568), he would have been totally remiss to not include one single instance of him practicing medicine alongside Paul, if that was indeed what he was doing.

It is most probable that Paul is simply making reference to what Luke did previous to his conversion. This would be like referring to the disciple Matthew as "Matthew, the tax collector" or to Peter as "the beloved fisherman." It would not be inaccurate to refer to these men in that way although they were not making a living by doing those things at that time.

Note 11 at Col. 4:14: Demas is later mentioned in 2 Timothy 4:10 as one who forsook Paul, having loved this present world.