George Leo Haydock

Luke. St. Luke was always much attached to St. Paul. It is thought he accompanied him to the time of his martyrdom. When St. Paul says Luke alone was with him, we must understand that no other disciple was at that time with him; not that the faithful of Rome, whose faith was so lively and charity so ardent, had abandoned him in this time of danger. (St. Chrysostom, hom. x. p. 610.) — Mark. This is John Mark, cousin of Barnabas, of whom mention was made, Acts xiii. 12. &c. also Colossians iv. 10. He rather wavered in faith at the beginning, but was afterwards much attached to the apostle. (Calmet)