CONCLUSION
As we have seen, Paul presented no credible biblical (or other) justification for his innovated doctrines. Quite bizarrely, in justifying his theology there was no appeal by Paul to what Jesus said or did; Christians would do themselves a service to reflect on this point. In fact, the one really good argument that Paul could not use is this: an appeal to the practice and teachings of Jesus. That would have been a legitimate appeal to authority – see what Jesus said and did. But Paul did not make this argument, precisely because he couldn’t – none of the teachings of Jesus in the New Testament advocate Paul’s theology such as Original Sin and justification by faith alone. This further proves that what Paul taught was at odds with what Jesus himself practiced. Paul morphed the very Jewish teachings of Jesus into an unrecognisable religion for Gentiles, by basing it on lies and abuses of the Old Testament.
Perhaps even more fatal to Paul’s claim of an Apostle is his alleged divine inspiration. Any inspired message from God should be infallible, as by definition God is infallible. In this blog post I have tried to be fair and evaluated Paul not by Islamic standards, which incidentally he would also fail, but rather based on his own bold claims within the New Testament. It has been shown that contrary to his own claims, Paul’s message was very fallible, so it stands to reason that Paul was not genuinely inspired by God. So I ask Christian readers, why then should we pay attention to his teachings? I’ll leave you with the words of Jesus:
“Beware of false prophets, which come to you in sheep’s clothing, but inwardly they are ravening wolves. Ye shall know them by their fruits…” [Matthew 7:15-16]

References.
1 – First Epistle to the Corinthians by C.K. Barrett, commentary on verse 52, page 381.