Bob Deffinbaugh comments on Paul’s testimony before Agrippa:
Paul did not describe his conversion as some kind of evolution, but rather as a radical transformation, a change from darkness to light, from death to life, a change from persecuting Christianity to practicing and promoting it. He was actively opposing the church when Jesus stopped him dead in his tracks and turned him around. He was not seeking the truth; he was convinced that he knew the truth, and that Christianity was a lie. He was not acting independently in his persecution of the Christian community; he had the full consent and authority of the chief priests.
At midday, when the sun would be at its brightest, Paul and those with him were smitten with a heavenly light, far brighter than the sun (verse 13). All fell to the ground, but only Paul heard the voice from heaven, spoken to him in the Hebrew dialect, “Saul, Saul, why are you persecuting Me? It is hard for you to kick against the goads”(verse 14). The light alone should have been terrifying to Saul, but the words which were spoken to him from heaven must have been even more troubling. The voice was a heavenly one, and Saul therefore rightly recognized the speaker as “Lord.” God was talking to Saul. And, God was somehow being persecuted by Saul. How could this be? Saul was persecuting Christians, followers of Jesus. The next words, “It is hard for you to kick against the goads,” are found only in this account, and not in the other two. These words seem to indicate that while Saul was strongly opposing Christianity, and at the same time persecuting the “Lord,” he was doing so in a futile effort, to his own loss. In our own vernacular, Paul was “shooting himself in the foot.”
Paul asked the inevitable and ultimate question, to make certain of the identity of the “Lord” who was speaking to him from heaven, “Who art Thou, Lord?”If Paul had not already figured it out, the voice supplied the answer: “I am Jesus whom you are persecuting.” Paul never argued this matter, not now, not ever. It was Jesus. He had been dead wrong. Jesus was alive! Therefore, Jesus was the promised Messiah, and the hope of Israel! And in persecuting the church, Paul was persecuting Jesus. In seeking to serve God according to his understanding of Judaism, he was actually opposing Him. The doctrine of the resurrection of the dead was now no longer a mere theory, but a reality. Jesus is alive. Jesus rose from the dead!