Originally, he was a Pharisee named Saul, who hated the early Christians for believing in Jesus, as his kind believed Jesus was breaking God's law. He watched the coats of the other Pharisees who were stoning St. Stephen. He wasn't intentionally a bad guy; he was just trying to protect the Jewish law and the traditions of his fathers, but he had lost God's sight. He had put Christians in jail. He was on his way to Damascus with his friends when a light shone on him from Heaven. "Saul, Saul, why do you persecute me?" asked the man in Heaven. When Saul asked Him who He was, He revealed that He was Jesus, whom he persecuted. He told Saul to arise and go to Damascus, where he would be told what to do. He was blinded and couldn't eat or drink anything for three days. Meanwhile, he repented of his sins. When a man named Ananias entered the House of Judas, he prayed for Saul to see again. Saul received his sight, and was then baptized by Ananias.
After baptism, Saul changed his name to Paul. He was being sought out by soldiers for "treason" and was assisted in being carried in a basket while being snuck out of Jerusalem. He preached and preached and preached and did good for other people. He even prayed to God for some people, and wrote letters, even through trials. Eventually, after his work was done, he was killed, but he wasn't afraid because he knew God loved him and he knew he'd live with them after his death. Some believe he was stoned just like Stephen, while others believe he was beheaded.