Luke and Acts form a two-part book, each revealing what Jesus accomplished among the first-century followers of Jesus. The Gospel of Luke focused on what Jesus began to do up to His ascension, Acts focuses on what Jesus continued to do after his ascension through the church, ending with the Gospel being proclaimed in Rome.
The two-part book Luke wrote makes up twenty-five percent of the New Testament. The size of the combined accounts makes the author the chief contributor to the New Testament. Luke and Acts, as a body of work, are larger than the combined writings of the Apostle Paul.
No doubt the book was written to Theophilus, a man about whom we can only make guesses as regards his identity. His name means "lover of God" so some assume the book is written to all "lovers of God”—unlikely.
Theophilus being "most excellent" by title was of equestrian rank (only the senatorial order was of higher status), a new believer, and had some deep interest in the life of Jesus and His activity among those who followed Him.
Many believe Theophilus funded Luke's gospel project, allowing him to investigate and gather research for the two-part book. Others go on to speculate that he was the lawyer who came from Antioch to defend Paul before Caesar, so Luke would have been gathering material concerning Jesus' life and ongoing ministry and the two-part book was the outcome of his research.
Luke's defense of Paul in this two-part book gave evidence of “The Way” regarding three matters:
a) Christianity had its origin in Judaism
b) Christianity was thus a recognized legal religion of Rome
c) it was non-seditious or subversive in nature, thus was not seeking an overthrow of Rome militarily or by means of earthly power
Christian faith as presented by Luke was, in fact, a harmless, innocent, and a lawful religion.
No doubt Luke was gathering information when Paul was in prison in Caesarea (24:27) probably between 60 and 62 A.D., being free to travel to Jerusalem, visit the sites, and interview eyewitnesses.
The Goals of the Gospel of Luke
The Gospel of Luke, along with Acts, accomplishes three goals.
1. A theological goal, revealing God's salvation
2. A historical goal, revealing the history of Jesus and His church
3. A judicial goal, providing a defense for Paul
Regarding salvation, Luke provides three pieces of evidence
a) He gives evidence of how salvation was promised
b) He gives evidence of how salvation was given through Christ
c) He gives evidence of how salvation was offered to all people beginning with the Jews first by Jesus and His disciples, then through Christ's apostles and the church
While the two-part book carries no immediate autograph from Luke, it is church tradition and internal evidence that make it obvious that Luke was the author.
Regarding church tradition, the early church fathers proclaim Luke the author. Luke was not an eyewitness, nor did he literally follow Jesus. He was instead a Gentile and likely a personal physician and traveling companion to the apostle Paul. There would have been ample reason for the early fathers to have wanted the book to be written by an eyewitness who actually followed Jesus. The fact that they attribute the work to Luke affirms the truth of authorship.
Second, the internal evidence within the two-part book is overwhelming. The book describes the writer as not being an eyewitness (1:2), removing from possibility any of the Lord's apostles. In Acts, there is what is known as the "we” passages, offering the largest clue to who the author is (Acts 16:10-17; 20:5-16; 21:1-18; and 27:1-28:16).
Scholars have accepted that Paul wrote Philemon, Colossians, and the Pastoral Epistles during his house arrest in that city. In studying those letters for references of those with Paul at that time, they developed a list of those who could have written Luke and Acts. In 2 Timothy 4:11, Paul says, “Only Luke is with me," making him the most likely person to have written Luke-Acts.
Basic Outline to Luke
The Infancy of the Son of Man (1:5–2:52)
The Preparation of the Son of Man for Public Ministry (3:1–4:13)
The Son of Man’s Galilean Ministry (4:14–9:50)
The Son of Man’s Journey to Jerusalem (9:51–19:27)
The Son of Man’s Jerusalem Ministry (19:28–21:38)
The Death and Resurrection of the Son of Man (22:1–24:53)