What does 2 Timothy 4:11 mean?

While many people had left Paul behind in Rome, for various reasons, Luke had remained. This is the physician (Colossians 4:14) who travelled as a missionary with Paul, including during his first imprisonment. He appears to have been extremely loyal to Paul, remaining as his final friend during his second imprisonment. In addition, he penned both the Gospel of Luke and the book of Acts. It's possible that Luke served as Paul's secretary for this letter, writing down his words. This, however, is uncertain.

A second friend is mentioned in this verse: Mark. This was John Mark, a young man whose mother hosted early believers in her home in Jerusalem. He travelled with Paul and Barnabas on their first missionary journey, leaving them early to return to Jerusalem. When Paul and Barnabas prepared for a second trip, they divided because Paul refused to take Mark with them, while Mark's relative Barnabas chose to remain with him and minister on the island of Cyprus. Mark later appears with Paul during his first arrest in Rome (Colossians 4:10; Philemon 1:24). Interestingly, Mark and Luke both wrote one of the Gospels, perhaps during this same time period in Rome.