When Abinadi entered the city, he had preached against king Noah, and, for that reason, had been brought before Noah and the court of priests. His fate was probably sealed at that time, but there was something about the law that they followed that required a different offense in order to be worthy of execution. When the priests began questioning him, it was clear that they knew that Abinadi had a different understanding of Jehovah than they did, and thus they began a line of questioning that would expose that difference.
Although Abinadi bore a powerful message that converted Alma, no others were moved. They deliberated and unsurprisingly found him guilty of what they would have considered blasphemy, a conviction meriting execution. What was his blasphemy? That God himself should come down among the children of men. This is, of course, exactly what Abinadi had preached and the entire reason for his discourse. Abinadi declared that the very Jehovah would, at a future date, come to earth to become the Messiah and provide the atonement.
The trial began with the expectation that Abinadi would be found guilty of blasphemy, and he was. The trial fulfilled their law, but it also fulfilled Jehovah’s purpose in that Alma believed. Alma’s belief led to important changes in the nature of Nephite religion, and probably its political system as well. It is possible that no single person, since Nephi, had as great an impact on the future direction of Nephite history than Alma himself.