Luke: The author of the Gospel of Luke and the book of Acts traveled with Paul at different times. Many believe Luke was Paul's physician (Colossians 4:14). Luke was the only one of Paul's fellow workers who stayed with him continually. Therefore, Paul wanted Timothy to come quickly.
Mark: Paul's belief that Mark would be useful shows a Christian story of amending differences (see Acts 13:13; 15:36–40; see also Colossians 4:10; Philemon 1:24).