Luke wrote the book of Acts as part two of his Gospel story. If we read Luke 1:1–4 with Acts 1:1–3 we see that both were addressed to “Theophilus.” The fact that Luke calls him “most excellent Theophilus” in Luke 1:3 indicates that he held some high government position. Because of this, some have suggested that Luke wrote this two-part story as a legal defense of Christianity, and particularly of the ministry of Paul, showing that the spread of the Christian faith was not a threat to the Roman Empire.
In the book of Acts, Luke gives a chronicle of the spread of the gospel message according to Jesus’ instructions (Matt. 28:18–20; Acts 1:7–8). At the same time, Luke shows the birth and development of the Church (Matt. 16:18), made up of all who believe in the Lord Jesus Christ as Savior. The baptism of the Holy Spirit (Acts 1:4–5; 2:1–12; 1 Cor. 12:13) created a new spiritual family and fulfilled the promise of the New Covenant (Jer. 31:31–34; Ezek. 36:25–27; Matt. 26:28; Mark 14:24; Luke 22:20; Heb. 8:6–12; 10:16–17; 12:24).
The foundation of the Church is the resurrection of Jesus Christ. To this historical fact, the early apostles faithfully testified. These men were supernaturally gifted with power to perform signs and miracles as proof of their divine appointment (Rom. 15:18–19; 2 Cor. 12:12). The powerful ministry and mighty deeds of the apostles are recorded for us in the book of Acts, ending with the ministry of the Apostle Paul.