The letters revealed some of the details of his life, although that was not their main purpose. He who had once scoffed at the very subject addressed hoped that his past would not keep his readers from giving serious consideration to his words.
Did he know then that some of his writings would be laboriously copied for others to read and ponder? Did he realize then that some of the meaning of his words might be lost in the translations that would follow?
All he wanted to do was to bear witness of what he'd come to know was true, for he had seen the resurrected Christ in a vision and became a follower of Him.
Other letters are included in the New Testament, but it is Paul's letters which make up the majority of what we have come to know as the epistles.