Of course, I always ask them - how is it then that Paul went from being the top Pharisee in charge of destroying Christianity (with a good job, prosperity, etc.) to being beaten and persecuted for this faith he was "making up".
Let's review Paul's own claims: (1 Corinthians 15:3)
"For I delivered unto you first of all that [the Gospel] which also I received"Paul claims the Gospel he is preaching is what he received from Jesus (on the road to Damascus). Also, Ephesians 1:1 -
"Paul, an apostle of Christ Jesus"The word "apostle" is transliterated from αποστολος ("apostolos"). It means "one sent out", like an ambassador. So it is "Paul, one sent from Christ Jesus".
Finally, Peter says (2 Peter 3:15):
"our beloved brother Paul also according to the wisdom given unto him hath written unto you"Peter supported everything Paul said (calling him a "beloved brother"). And acknowledged Paul's words as coming from God ("wisdom given unto him").
Paul wrote most of the New Testament (especially if you include Luke's writings). That is because he is the Apostle to the Gentiles (Romans 11:13). Gentiles had no understanding from the Old Testament. Paul's writings also did much to help with reconciling Jewish and Gentile Christians.