What does Acts 9:22 mean?

Saul had been trained by a well-respected rabbi of his time (Acts 22:3). He intimately knew every detail of the Hebrew Scriptures—what we now call the Old Testament. As a student of the Pharisees, he believed the Messiah was coming and that the faithful dead would be resurrected.

Many Jewish men had the same education, however, and never came to the realization that Jesus is the Messiah. Saul had the advantage of having listened to Stephen's testimony. Stephen took his listeners on a trip through Jewish history, showing them that their forefathers had been saved by God before the nation of Israel, the occupation of Jerusalem, the construction of the temple, or the establishment of the sacrifices. And yet, the Israelites constantly rebelled against God, including killing His prophets. In the same way, they killed the prophet Moses had promised would follow him: Jesus (Acts 7).

At the time, Saul was happy to see Stephen murdered by the mob (Acts 7:58). He was incensed that anyone could preach against the temple and the Law and made it his mission to hunt Jesus-followers to extinction (Acts 26:9–11).

All the extensive training and background information made him a formidable evangelist when Saul began preaching that Jesus is the Messiah, but that same education had not initially convinced him of the truth of Jesus. Saul came to Jesus because Jesus chose him (Philippians 3:12). Saul's conversion shows that God doesn't let us reason our way to Him (Matthew 13:14–15; 1 Corinthians 1:18–25). Stephen spoke so convincingly, his audience was unable to refute his arguments, so they lied about him and killed him (Acts 6:10–14; 7:54–60). God calls us and rescues us, by grace, through faith, not by our own efforts, whether mental or physical (Ephesians 2:8–9).