Prior to conversion Paul seems to be at maximum antichristianity.
On his confrontation with Jesus which Jesus initiates. Jesus confronts Paul with his true mission to personally persecute Jesus. Paul's true motivation is revealed and Paul does not later deny his true motivation. Psychologically Paul had been in denial of what it was he was really railing against.
Okay - let's have a couple of quotes from Bernard Shaw. I found them interesting, but naively oblivious of the biblical scholarship which had done a lot of textual dissection even in his time. He seems to take the texts as he finds them - assuming everything attributed to Paul is in fact by him, and more importantly, presuming that we can actually trust the gospels as reliable reportage.
Nonetheless; here he is on Paul's conversion:
Suddenly a man of genius, Paul, violently anti-Christian, enters on the scene, holding the clothes of the men who are stoning Stephen. He persecutes the Christians with great vigor, a sport which he combines with the business of a tentmaker. This temperamental hatred of Jesus, whom he has never seen, is a pathological symptom of that particular sort of conscience and nervous constitution which brings its victims under the tyranny of two delirious terrors: the terror of sin and the terror of death, which may be called also the terror of sex and the terror of life. Now Jesus, with his healthy conscience on his higher plane, was free from these terrors. He consorted freely with sinners, and was never concerned for a moment, as far as we know, about whether his conduct was sinful or not; so that he has forced us to accept him as the man without sin. Even if we reckon his last days as the days of his delusion, he none the less gave a fairly convincing exhibition of superiority to the fear of death. This must have both fascinated and horrified Paul, or Saul, as he was first called. The horror accounts for his fierce persecution of the Christians. The fascination accounts for the strangest of his fancies: the fancy for attaching the name of Jesus Christ to the great idea which flashed upon him on the road to Damascus, the idea that he could not only make a religion of his two terrors, but that the movement started by Jesus offered him the nucleus for his new Church.
And this on the subsequent developments of Christianity reliant on his view of things:
Paul must soon have found that his followers had gained peace of mind and victory over death and sin at the cost of all moral responsibility; for he did his best to reintroduce it by making good conduct the test of sincere belief, and insisting that sincere belief was necessary to salvation. But as his system was rooted in the plain fact that as what he called sin includes sex and is therefore an ineradicable part of human nature (why else should Christ have had to atone for the sin of all future generations?) it was impossible for him to declare that sin, even in its wickedest extremity, could forfeit the sinner's salvation if he repented and believed. And to this day Pauline Christianity is, and owes its enormous vogue to being, a premium on sin. Its consequences have had to be held in check by the worldlywise majority through a violently anti-Christian system of criminal law and stern morality. But of course the main restraint is human nature, which has good impulses as well as bad ones, and refrains from theft and murder and cruelty, even when it is taught that it can commit them all at the expense of Christ and go happily to heaven afterwards, simply because it does not always want to murder or rob or torture.
(From the Preface to
Androcles and the Lion)