Final answer:
Paul's work had the effect of spreading Christianity through his teachings and evangelism efforts.
Step-by-step explanation:
The effect of Paul's work was that he spread Christianity. As a Jewish leader who converted to Christianity, Paul played a crucial role in popularizing the belief that Jesus's death on the cross was part of a divine plan to cancel out human sin. Paul traveled to Greek and Roman cities, such as Ephesus, Corinth, Thessalonica, and Rome, where he encountered the Greco-Roman religious and cultural experience. His teachings and evangelism efforts led to the growth and expansion of Christianity in the ancient Mediterranean world.