When did Saul become a believer?

Although Saul heard of the followers of Jesus and their teaching, the seed of Saul’s conversion were first planted when he was among the Jews that heard Stephens speech and him saying he saw the glory of God-Jesus at the right hand of God in heaven and called upon him to forgive these men for what they were about to do.

Acts 7:55-59: “But he, being full of the Holy Spirit, gazed into heaven and saw the glory of God, and Jesus standing at the right hand of God, and said, "Look! I see the heavens opened and the Son of Man standing at the right hand of God!" Then they cried out with a loud voice, stopped their ears, and ran at him with one accord; and they cast him out of the city and stoned him. And the witnesses laid down their clothes at the feet of a young man named Saul. And they stoned Stephen as he was calling on God and saying, "Lord Jesus, receive my spirit.

Paul recalls this event in Acts 22:20-21: “when the blood of Your martyr Stephen was shed, I also was standing by consenting to his death, and guarding the clothes of those who were killing him.”

Saul (Paul’s) conversion is recorded in Acts 9:3-8, when he encounters a blinding light coming out of heaven which Paul calls a great light. (Acts 22:6-11) He describes it as brighter than the sun (Acts 26:13-18) (like the one that came from Jesus when he was transformed before his disciples on the mount of Transfiguration). Paul knew about his forefathers encountering God’s glory and so he immediately bows his will to its presence. We also read of the voice of Jesus speaking from heaven on the Damascus Road to Paul, just as God the Father spoke from heaven at Jesus’ baptism and on the Mt. of Transfiguration to the disciples. Jesus identifies himself to Paul as the one He is opposing, in so doing this he is fighting against God. It is at this time Paul was born again and became a believer.

Acts 9:6, Paul, after falling to the ground and hearing the Lord, says to Jesus, “Lord, what will you have me do?” (He repented of his unbelief calling Jesus his Lord and he is ready to serve him.) In verse 15, the Lord tells Ananias he is a chosen vessel (separated from birth Gal 1:15). He is being sent to the Gentiles to preach the gospel.

Acts 22:12-15 “Ananias, a devout man according to the law, having a good testimony with all the Jews who dwelt there, 13 came to me; and he stood and said to me, 'Brother Saul, receive your sight.' And at that same hour I looked up at him. 14 Then he said, 'The God of our fathers has chosen you that you should know His will, and see the Just One, and hear the voice of His mouth. 15 For you will be His witness to all men of what you have seen and heard.”

Acts 22:6-9 “as I journeyed and came near Damascus at about noon, suddenly a great light from heaven shone around me. 7 And I fell to the ground and heard a voice saying to me, 'Saul, Saul, why are you persecuting Me?' 8 "So I answered, 'Who are You, Lord?' And He said to me, 'I am Jesus of Nazareth, whom you are persecuting.'

In Acts 26:15- 18, when Paul is giving his testimony to King Agrippa, he states that,  "So I said, 'Who are You, Lord?' And He said, 'I am Jesus, whom you are persecuting. 16 But rise and stand on your feet; for I have appeared to you for this purpose, to make you a minister and a witness both of the things which you have seen and of the things which I will yet reveal to you. 17 I will deliver you from the Jewish people, as well as from the Gentiles, to whom I now send you, 18 to open their eyes, in order to turn them from darkness to light, and from the power of Satan to God, that they may receive forgiveness of sins and an inheritance among those who are sanctified by faith in Me.'

We see Paul is called a witness called to preach In 1 Cor.2:8 Paul writes that “none of the rulers of this age knew, for if they had known, they would not have crucified the Lord of glory.” Jesus Christ who was crucified was to Paul the King and Lord of glory of the Old Testament, he knew this immediately when he encountered him on the Damascus road.