Saul of Tarsus, noted Pharisee, with a good conscience persecuted believers. He thought they were worthy of death because they followed Jesus of Nazareth, who claimed to be Messiah and the Son of God. So Saul had letters from the authorities giving him permission to arrest and have transported to Jerusalem for trial any followers of Jesus that he might find (Acts 9).

Jesus appeared to Saul, changed Saul’s name to Paul, and sent him blinded to Damascus to wait on a messenger. After three days, Jesus sent Ananias to tell Paul what he needed to do. Paul, a penitent believer, was healed of his blindness and instructed, Acts 22:16--

"Now why do you delay? Get up and be baptized, and wash away your sins, calling on His name.” NASU

Paul thus became an Apostle to the Gentiles, special envoy to the nations of Asia and Europe. He suffered many afflictions while in this duty, as listed in his letter to the Corinthian Christians in answer to his detractors who questioned his authority, 2 Cor 11:23-27--

“in far more labors, in far more imprisonments, beaten times without number, often in danger of death. Five times I received from the Jews thirty-nine lashes. Three times I was beaten with rods, once I was stoned, three times I was shipwrecked, a night and a day I have spent in the deep. I have been on frequent journeys, in dangers from rivers, dangers from robbers, dangers from my countrymen, dangers from the Gentiles, dangers in the city, dangers in the wilderness, dangers on the sea, dangers among false brethren; I have been in labor and hardship, through many sleepless nights, in hunger and thirst, often without food, in cold and exposure.” NASU

A breaking point in the ministry of Paul occurred with his stoning at Lystra (Acts 14). Here Paul learned to trust in God who raises the dead (2 Cor 1:8-10). Previously Paul trusted his own provisions too much, even to the point of arranging to be let down over the Demascus city wall in a basket to escape danger (Acts 9:25). Now Paul was different. After visiting a neighboring city to preach the gospel, he returned to Lystra and encouraged the believers there. Never again would Paul rely on his own strength to escape harm, but he voluntarily went up to Jerusalem to face those who desired his death, and from there went to Rome, where years later Paul would be killed by Nero.

Paul explained how he once pleaded to Jesus to heal him, 2 Cor 12:7-10—

“Because of the surpassing greatness of the revelations, for this reason, to keep me from exalting myself, there was given me a thorn in the flesh, a messenger of Satan to torment me -- to keep me from exalting myself! Concerning this I implored the Lord three times that it might leave me.”
“And He has said to me, ‘My grace is sufficient for you, for power is perfected in weakness.’ Most gladly, therefore, I will rather boast about my weaknesses, so that the power of Christ may dwell in me. Therefore I am well content with weaknesses, with insults, with distresses, with persecutions, with difficulties, for Christ's sake; for when I am weak, then I am strong.”

Perhaps one of the greatest lessons all Christians need is to learn to trust the Lord, who raises the dead. We therefore need not fear death, because Jesus has already vanquished death with His resurrection and the sure hope believers have in our own promised resurrection.

We can be used of the Lord in marvelous ways when we lose our fear of failure and death, and learn to trust the Power of God to provide what is needed for the fight. As we study the scriptures, we should trust the desired outcome as explained by Paul, 1 Tim 1:5—

“But the goal of our instruction is love from a pure heart and a good conscience and a sincere faith.” NASU

Before Saul met Jesus, he had a good conscience about doing bad things. After Paul met Jesus, he learned to have a pure heart, a good conscience, and sincere faith through learning to trust Jesus for life. We need our conscience to be trained by Jesus, so that we have the desire to be like Him with love from a pure heart and sincere faith.