Why is Paul's gospel different from what Jesus taught before the cross?
Paul's gospel differs because he did not receive it from men or by human teaching; it came by revelation of Jesus Christ after the cross, resurrection, and ascension, when Christ was in Heaven and Glory. The four Gospel accounts occurred before the work of the cross, while Paul was commissioned to tell the whole world.
Les explains that Paul's gospel was different because Paul did not receive it from man or get taught it by men. He received it by the revelation of Jesus Christ. At that time Christ was in Heaven and Glory after His resurrection, not giving the pre-cross teaching recorded in the four Gospels. Les points out that the four Gospel accounts took place before the work of the cross, but Paul received his message after the cross was accomplished and after Christ ascended back to Glory. Paul was then told what to tell the whole world—not just the Jew or Gentile, but all the world. Les also notes Paul's former life in the Jews' religion, when he persecuted the church, or assembly, and wasted it.