Mormon does not describe Alma’s repentance, but it certainly required a complete change of mind and ways. Alma was converted in the true sense of being changed from one state to another. Once a presumably firm supporter of the king and his apostate religion, he now teaches the gospel as Abinadi had explained it, especially its primary belief in the Atoning Messiah. There is no indication that Alma needed to learn any other doctrine to understand and teach the gospel.
Alma must have known that his life was in danger. Regardless, he “went about privately among the people.” Perhaps people were willing to listen to Alma where they had not listened to Abinadi because Alma had been one of the court priests. Perhaps they listened because they understood that Alma was giving up earthly prestige, position, rank, and wealth—and risking his life—to follow the heavenly message. He was a walking testimony to the power of Abinadi’s message.