Luke is the author of two books in the New Testament which are probably two volumes of the same book: Luke and Acts. Modern research has shown him to be a historically accurate author.
Luke was a gentile who was sometimes referred to as Lucas and little is known of his early history, although we do know he was a physician. He was one of Paul’s missionary companions, as shown in Acts 10, when Luke begins to write about the events as “we” after Paul had a vision to come to Macadonia. It was on this visit they met Lydia, the seller of purple, but Luke was not arrested with Paul and Silas.
Luke is mentioned as sending greetings to the Colossians in chapter 4. In Rome, when Paul was captured and put before Nero the second time, the others had left, and Demas was listed as having forsaken Paul for the world. Only Luke remained faithfully with Paul, having joined him in Philippi, where it appears he had been for several years. It was at this time Paul offered his well-known testimony:
7 I have fought a good fight, I have finished my course, I have kept the faith:
8 Henceforth there is laid up for me a crown of righteousness, which the Lord, the righteous judge, shall give me at that day: and not to me only, but unto all them also that love his appearing (2 Timothy 4).
We do not know what became of Luke in later years, but there is a tradition that he was martyred. The Joseph Smith translation of the Bible records that he became a messenger of Jesus Christ after his death.