Introduction to Luke

This evangelist is generally supposed to have been a physician, and a companion of the apostle Paul. The style of his writings, and his acquaintance with the Jewish rites and usages, sufficiently show that he was a Jew, while his knowledge of the Greek language and his name, speak his Gentile origin. He is first mentioned Acts 16:10,11, as with Paul at Troas, whence he attended him to Jerusalem, and was with him in his voyage, and in his imprisonment at Rome. This Gospel appears to be designed to supersede many defective and unauthentic narratives in circulation, and to give a genuine and inspired account of the life, miracles, and doctrines of our Lord, learned from those who heard and witnessed his discourses and miracles.

-- taken from Matthew Henry's Concise Commentary