“It seemed good to me… to write unto thee… most excellent Theophilus” (Luke 1:3).
“The former treatise have I made, O Theophilus…” (Acts 1:1).
As you can see, both the Book of Luke and the Book of Acts were written by Luke to a man named Theophilus. We’re not really sure who Theophilus was, since the Bible only mentions him in these two references. But all names have meanings, and in the Bible, the meaning of names often has spiritual significance. Of course, a Pastor used to joke that Theophilus got his name when he was born, and his father said, “That’s the-awful-est looking kid I’ve ever seen!”
The name Theophilus actually means “Friend of God.” That’s significant, for in the Bible, only “Abraham… was called the friend of God” (James 2:23 cf. 2 Chron. 20:7). So when Luke wrote his gospel to a man named Theophilus, that’s one of the many ways God tells us that Luke’s gospel is written to Jews, the seed of Abraham, the friend of God.
Now I know that that’s not what most Christians believe. Most Christians think that Luke was written for us, members of the Body of Christ, living in the dispensation of grace. But the Book of Luke describes the earthly life of the Lord Jesus, and Paul tells us that “Jesus Christ was a minister of the circumcision…” (Rom. 15:8). So the Gospel of Luke is written to and for and about the Jews.
But if the Book of Acts is also written to Theophilus, that tells you that it too was written with the Jews in mind. That’s important to remember, for most Christians believe that the first two chapters of Acts are not a continuation of what had come before, but the start of something new. They believe it was the beginning of “the church, which is His Body” (Eph. 1:22,23).
But if Luke says that his first treatise was about “all that Jesus began to do and teach” the Jews (Acts 1:1), then this second treatise must be about all that the Lord continued to do and teach the Jews — through the twelve apostles. It is only after the Lord’s friends in the house of Israel stoned Stephen, showing that they refused to repent of wounding Him in the house of His friends (cf. Zech. 13:6), that Luke records how God interrupted His ministry to Israel by saving Paul and sending him to the Gentiles.
That means that Paul’s conversion marks the beginning of the church of today, not Pentecost! And that means that the specific information you need to live your Christian life is found in his epistles. source