Luke, the writer of the Gospel and the Acts of the Apostles, has been identified with St. Paul's "Luke, the beloved physician" (Colossians 4:14). We know few other facts about Luke's life from Scripture and from early Church historians.
It is believed that Luke was born a Greek and a Gentile. In Colossians 10-14 speaks of those friends who are with him. He first mentions all those "of the circumcision" -- in other words, Jews -- and he does not include Luke in this group. Luke's gospel shows special sensitivity to evangelizing Gentiles. It is only in his gospel that we hear the parable of the Good Samaritan, that we hear Jesus praising the faith of Gentiles such as the widow of Zarephath and Naaman the Syrian (Lk.4:25-27), and that we hear the story of the one grateful leper who is a Samaritan (Lk.17:11-19). According to the early Church historian Eusebius Luke was born at Antioch in Syria.
In our day, it would be easy to assume that someone who was a doctor was rich, but scholars have argued that Luke might have been born a slave. It was not uncommon for families to educate slaves in medicine so that they would have a resident family physician. Not only do we have Paul's word, but Eusebius, Saint Jerome, Saint Irenaeus and Caius, a second-century writer, all refer to Luke as a physician.
We have to go to Acts to follow the trail of Luke's Christian ministry. We know nothing about his conversion but looking at the language of Acts we can see where he joined Saint Paul. The story of the Acts is written in the third person, as an historian recording facts, up until the sixteenth chapter. In Acts 16:8-9 we hear of Paul's company "So, passing by Mysia, they went down to Troas. During the night Paul had a vision: there stood a man of Macedonia pleading with him and saying, 'Come over to Macedonia and help us.' " Then suddenly in 16:10 "they" becomes "we": "When he had seen the vision, we immediately tried to cross over to Macedonia, being convinced that God had called us to proclaim the good news to them."
So Luke first joined Paul's company at Troas at about the year 51 and accompanied him into Macedonia where they traveled first to Samothrace, Neapolis, and finally Philippi. Luke then switches back to the third person which seems to indicate he was not thrown into prison with Paul and that when Paul left Philippi Luke stayed behind to encourage the Church there. Seven years passed before Paul returned to the area on his third missionary journey. In Acts 20:5, the switch to "we" tells us that Luke has left Philippi to rejoin Paul in Troas in 58 where they first met up. They traveled together through Miletus, Tyre, Caesarea, to Jerusalem.
