With the conversion of gentiles in the Cornelius story, the story of Acts now reaches a turning point.
Up to now, Peter has been the main human character. Jerusalem has been the center for spread of the gospel. The gospel focus has been in the region of the Holy Land. Barnabas has been a minor character with an important supporting role – an encourager of the Church. All of this changes with Acts 13.
Saul, who became a Christian in chapter nine has had almost no role at all. As he and Barnabas undertake a mission trip, Saul is the helper. Barnabas is the leader. But in a heartbeat, that changes. Opposed and maligned before the chief political official of Cyprus, Saul steps to the forefront and becomes the leader of the delegation, and he remains the central human figure through the rest of the book. He also gets a name change and becomes”Paul,” the home base for mission work becomes Jerusalem and the reach is no longer confined to one area, but expands to cover the Roman world. This is called “Paul’s First Missionary Journey.”
In Antioch of Pisidia we have Paul’s first sermon. Preached to Jews, it opens covering much the same territory as Stephen’s speech in chapter seven: it focuses on what God has done, culminating in the work of Jesus. Then, it is like the sermon Peter preached in Acts 2, demonstrating that Jesus had to be the Son of God, the promised Messiah, proving the point by the resurrection.
Like Stephen’s sermon, the message was rejected by Paul’s Jewish hearers, but accepted by the gentiles, and this is Luke’s way of changing the focus of the Christian mission. Jews will be included wherever Paul Preaches, but the message and story of the book now focuses on the gentiles.