"I am a Jew, born in Tarsus in Cilicia, but brought up in this city at the feet of Gamaliel, educated strictly according to our ancestral law, being zealous for God, just as all of you are today. I persecuted this Way up to the point of death by binding both men and women and putting them in prison, as the high priest and the whole council of elders can testify about me. From them I also received letters to the brothers in Damascus, and I went there in order to bind those who were there and to bring them back to Jerusalem for punishment.
"While I was on my way and approaching Damascus, about noon a great light from heaven suddenly shone about me. I fell to the ground and heard a voice saying to me, ‘Saul, Saul, why are you persecuting me?' I answered, ‘Who are you, Lord?' Then he said to me, ‘I am Jesus of Nazareth whom you are persecuting.' Now those who were with me saw the light but did not hear the voice of the one who was speaking to me. I asked, ‘What am I to do, Lord?' The Lord said to me, ‘Get up and go to Damascus; there you will be told everything that has been assigned to you to do.' Since I could not see because of the brightness of that light, those who were with me took my hand and led me to Damascus.
"A certain Ananias, who was a devout man according to the law and well spoken of by all the Jews living there, came to me; and standing beside me, he said, ‘Brother Saul, regain your sight!' In that very hour I regained my sight and saw him. Then he said, ‘The God of our ancestors has chosen you to know his will, to see the Righteous One and to hear his own voice; for you will be his witness to all the world of what you have seen and heard. And now why do you delay? Get up, be baptized, and have your sins washed away, calling on his name.'
Jesus said to his disciples, "Go into all the world and proclaim the good news to the whole creation. The one who believes and is baptized will be saved; but the one who does not believe will be condemned. And these signs will accompany those who believe: by using my name they will cast out demons; they will speak in new tongues; they will pick up snakes in their hands, and if they drink any deadly thing, it will not hurt them; they will lay their hands on the sick, and they will recover."
In his book: Paul, a Critical Life the late Fr. Jerome Murphy O'Connor o.p. shows what a reversal of values took place in the mind of Paul the Pharisee, once he recognises the divine mandate and authority of the risen Christ. As a young scholar in Jerusalem, Saul/Paul must have already known some of the facts about Jesus."It is inconceivable that he should have persecuted Christians without learning something about the founder of the movement. He certainly was in a position to discover as much as Josephus did. Thus we can safely assume that Paul knew, that Jesus had been a teacher to whom wonders were ascribed; that he had been crucified under Pontius Pilat; and that his followers thought of him as the Messiah. It is unlikely that he would have been content with such bare bones. Pharisaic interests would have driven him to flesh them out." The Pharisaic version of Jesus' activities differed from that of Jesus' followers. His attitude of unperturbed authority, however, would have hinted at an attitude towards the Law embodying a personal claim that made closer attention to his teaching imperative. Paul would have known that "Jesus thought of himself as the Messiah empowered to articulate God's will; the Law was no longer the sole or final authority."
While there may be some hesitancy in determining what Paul knew of Jesus while still a Pharisee, there can be no doubt as to what he thought of Christian claims. To his way of thinking it was ridiculous to maintain that God had intervened to raise from the dead a false teacher whose blasphemous claim to be the Messiah went hand in hand with deliberate subversion of the authority of the Law. The reason why Paul tried to turn Christians from their beliefs was that in his view they had been disastrously misled. Jesus, Paul was convinced, had died a fitting death, and all that remained was the return of his supporters to the fold of authentic Judaism. Paul explicitly reports that Jesus took the initiative in the encounter that led to his conversion; there had been no preparation on his own part.
How did Paul recognise Jesus, whom he had never seen in his life? "By definition, he could not have recognized Jesus on the same basis as those who had come with him from Galilee to Jerusalem. We can be sure, however, that Paul had a mental image of Jesus…. What actually happened must remain a mystery unless we are prepared to invoke the vivid details of Luke's accounts, in each of which, incidentally, Jesus has to identify himself, Acts 9:5; 22:8; 26:15. In any event, the reality and the mental image fused and Paul's world was turned upside down."
"Paul now knew with the inescapable conviction of direct experience that the Jesus who had been crucified under Pontius Pilate was alive. The resurrection which he had contemptuously dismissed was a fact, as undeniable as his own reality. He knew that Jesus now existed on another plane. This recognition is all that was necessary to his conversion, because it completely transformed his value system. No longer were the claims of Jesus the blasphemous pretensions of a madman, but utter truth. Jesus, therefore, must be precisely what he implicitly, and his disciples explicitly, claimed he was, namely, the Messiah."
"Only when it is conceded that Paul's conversion consisted essentially in the revaluation of ideas which he already possessed does it become possible to understand how he can write, ‘For I would have you know, brethren, that the gospel preached by me is not according to man, for I did not receive it from man nor was I taught it but it came through a revelation of Jesus Christ.' This embodies a slight deviation from the absolute truth which is excused by the polemic context. No one convinced of the truth of Jesus had taught Paul about Christ or Christianity. He had never studied them in the way that he had studied the Law.
Paul's encounter with Christ revealed the truth of what he had once taken as falsehood by forcing a new assessment of what would become the core of his gospel. Christ was the new Adam, the embodiment of authentic humanity. The Law was no longer an obstacle to the salvation of Gentiles; they could be saved without becoming Jews. And according to Paul, his conversion was for the sake of the Gentiles, ‘But when he who had set me apart from my mother's womb, and had called me through his grace, was pleased to reveal his son to me, in order that I might preach him among the nations.'