Paul was baptized by Ananias in the river of Damascus. He was then strengthened by food, and immediately began to preach Jesus to the believers in the city, the very ones whom he had set out from Jerusalem with the purpose of destroying. He also taught in the synagogues that Jesus who had been put to death was indeed the Son of God. His arguments from prophecy were so conclusive, and his efforts were so attended by the power of God, that the opposing Jews were confounded and unable to answer him. Paul's rabbinical and Pharisaic education was now to be used to good account in preaching the gospel and in sustaining the cause he had once used every effort to destroy. SR 273.2
The Jews were thoroughly surprised and confounded by the conversion of Paul. They were aware of his position at Jerusalem, and knew what was his principal errand to Damascus, and that he was armed with a commission from the high priest that authorized him to take the believers in Jesus and to send them as prisoners to Jerusalem; yet now they beheld him preaching the gospel of Jesus, strengthening those who were already its disciples and continually making new converts to the faith he had once so zealously opposed. Paul demonstrated to all who heard him that his change of faith was not from impulse nor fanaticism, but was brought about by overwhelming evidence. SR 274.1
As he labored in the synagogues his faith grew stronger; his zeal in maintaining that Jesus was the Son of God increased in the face of the fierce opposition of the Jews. He could not remain long in Damascus, for after the Jews had recovered from their surprise at his wonderful conversion and subsequent labors, they turned resolutely from the overwhelming evidence thus brought to bear in favor of the doctrine of Christ. Their astonishment at the conversion of Paul was changed into an intense hatred of him like unto that which they had manifested against Jesus. SR 274.2