The king gave Paul permission to speak, and Paul raised his hand in salutation to Agrippa (Acts 26:1). The Greek expression is different here. In both Acts 13:16 and in 21:40 the gesture was intended to invite silence, but here Paul meant to express respect to the king’s office. He began by admitting it was his (Paul’s) honor to discuss his case before Agrippa, whom, Paul claimed, was well aware of the traditions of the Jews, as well as those matters in which they vigorously debated among themselves (Acts 26:2-3). Thus, with the matter of his being accused of treason against Caesar taken out of the way by Festus (Acts 25:25, cp. 25:18-19), Paul framed his charges around that of Jewish tradition and theology.
Far from being raised as a renegade Jew, Paul was brought up at Jerusalem and, according to the strictest sect of Judaism, he lived a Pharisee. It was according to the very theological issue that the Pharisees embrace that Paul stood before Agrippa accused by the elders at Jerusalem. Imagine, for the very hope and promise God made to the fathers of the nation, for which all the twelve tribes served God throughout their history Paul stood accused before the king opposed by the Jewish leaders themselves (Acts 26:4-7)! Why should it be a controversy that God raises dead people (Acts 26:8)?
It wouldn’t be appropriate for Paul to accuse the leaders of his nation of fanatical wrong doing before the king. Not only wouldn’t it have been appropriate, because they were absent and couldn’t answer Paul’s charges, but it wouldn’t be appropriate, because the Scriptures command us not to revile the rulers of the nation (Exodus 22:28; cp. Ecclesiastes 10:20 and Acts 23:5). Agrippa would know this Scripture and would resent Paul doing so, if Paul chose to make this point. Agrippa would resent such activity not only for the Scriptures sake, but because he also was a ruler of the people and would tend to take their part. Rather, therefore, Paul began to testify of his own fanaticism against the Way in the service of the leaders of the Jews (cp. Acts 26:12)!
Luke means for us to see the fanatical fury of the Jewish leaders toward the Way, and the argument upon which they stood in defending their decision to do so, in Paul’s own fanaticism against the Way. Paul’s own confession of wrongdoing is itself an accusation against the Jewish leaders. When Paul confesses that he persecuted Messianic believers, we are expected to see the hearts of Paul’s accusers in Paul’s own heart as a persecutor. As Paul was, so were they at this point in time. Jesus of Nazareth was Paul’s Rock of offense (cp. Acts 26:9). How could he who is cursed of God (Deuteronomy 21:23) be the Messiah? Jesus was hung on a tree and was, therefore, cursed of God, and all those who would follow such a man make themselves the enemies of God, because they profess the righteousness of one whom God cursed and in effect make God unrighteous.
This was behind Paul’s activity, and Luke means for us to see that Paul, in presenting himself this way, defines the hearts of those who accuse him before the king. All Messianics, including Paul at this time whether at Jerusalem or in the Diaspora, must recant, repent, abandon the Way or die (Acts 26:10-11). Orthodox behavior is not an issue; the followers of a cursed man are apostates, the enemies of God. This is fanaticism—whether it was done by Paul in the service of the leaders of the Jews or to Paul by those same leaders who have made themselves his accusers.
What changed Paul? He met Jesus in a heavenly vision (Acts 26:12-15). As long as theology was a theory, the point was arguable, but once that theology was given life in the resurrected Jesus—a Theophany—Paul was undone. He had to admit that the Cursed One was Lord! Jesus was the Elect One—the Messiah of God. The Light above all other lights had broken through Paul’s fanaticism.
What does all this mean? I believe Luke means to show us that Paul, like Jesus, was to give light to the blind (Acts 26:18; cp. Luke 4:18; 7:21-22). Paul was to bring light and to be light (Acts 13:47). Jesus’ resurrection (Acts 26:23) is seen in Paul’s own life. Saul (the old Paul) died on the Damascus road, and it is just as difficult to explain the new Paul apart from resurrection as it is to explain the empty tomb in Jerusalem apart from resurrection. Jesus sent Paul to witness concerning what he had seen just outside Damascus, which is intended to enlighten both the Jews and the gentiles (Acts 26:16-18). So, Paul now testified before Agrippa of his obedience (Acts 26:19) to the vision, as he preached forgiveness to both Jew and gentile, transferring the believer from the kingdom of darkness (the world) to the Kingdom of Light (God).
 See F.F. Bruce, The Book of Acts, page 488.