Final answer:
The apostle Paul wrote the largest portion of the Epistles in the New Testament.
Step-by-step explanation:
The largest portion of the Epistles in the New Testament was written by the apostle Paul. Paul was a Jewish leader who underwent a conversion experience and became a prominent Christian evangelist. His Epistles, such as Romans, Corinthians, and Ephesians, played a major role in spreading Christianity to various cities in the ancient Mediterranean world.