Paul persecuted the nascent Church, because he believed that the fact Jesus was crucified indicated both he and his message were cursed by heaven (Deuteronomy 21:23). One might conclude that not only was he responsible for Stephen’s death, but that he was also behind the first persecution of the Church (Acts 7:58-60; 8:1, 3). As a result of the posture Paul assumed toward believers in Jesus, he became the Jewish authorities’ go-to person to get the job done concerning putting down this new Jewish movement (Acts 9:1-2). He excelled where others failed (Galatians 1:14).
It is, therefore, apparent that Paul had a great deal to lose by believing the Gospel. He had persecuted believers up until the very time of his revelation of Christ from heaven (Acts 9:3-4). By turning to Jesus, Paul lost everything he had worked for up until the event of his Damascus experience. None of the Jewish authorities would have backed his new found faith. Whatever Paul had hoped to gain in Judaism, would now be no longer attainable. The point is that the only way Paul could have understood the truth about Christ was by direct revelation from God (Galatians 1:12, 15-16). If Paul was bent on destroying the Church until the moment he became a believer, he couldn’t have received such a life-changing experience from the Apostles’ testimony, because it was that very testimony that he was determined to blot out. Paul was on the road to success among his people, doing what others failed to do for the Jewish authorities. Nothing he was learning in Judaism before his journey to Damascus would have revealed to Paul the truth about Jesus. Therefore, the only reasonable way Paul could have learned the truth about Jesus was through a revelation from God.
One might ask what Paul meant by God separating him from his mother’s womb. Many believe this is a reference to Paul’s human birth, but I believe it refers to his new birth in Christ. His mother is Judaism itself, from which God separated him through calling him to Christ (Galatians 1:15; cp. Revelation 12:1-2, 5). Paul is describing being born again. If Paul didn’t believe the Apostles’ testimony, and if he was seeking to destroy the nascent Church, and if he was pursuing a successful career in Judaism that was not according to the truth, then Paul was called by the grace of God. Nothing he was doing would have led to his receiving Christ—the call was a complete shock. Paul was born from above through the call of God that revealed the Son of God (Jesus) in Paul (Galatians 1:15-16).
Immediately, Paul went into Arabia. He did not consult with believers in Damascus, neither did he return to Jerusalem to consult with the Apostles (Galatians 1:16-17). Moreover, Luke’s account agrees (Acts 9:20-25). He shows Paul immediately preaching the Gospel in Damascus, so Paul’s excursion into Arabia (Galatians 1:17) probably needs to be understood as an evangelistic mission, as well as a learning mission. Paul already knew the basics of the Gospel—Jesus was crucified, but God raised him from the dead, and now Jesus is Lord/Messiah. This is what the vision of Christ revealed to Paul, and it did not need the testimony of others to confirm its content. The fact that a previously unknown disciple, Ananias, told a blind Paul in Damascus of the vision he had of Jesus was confirmation enough that what Paul experienced was not a dream or a trance. Rather, it was an actual vision of the resurrected Lord. Therefore, Paul was sufficiently equipped to preach to others that Jesus was, indeed, the Messiah.