Aaron, a son of King Mosiah², was at first an unbeliever and a persecutor of the church of God, going about with his brothers and Alma the Younger to destroy it (Mosiah 27:8-10, 32). An angel of the Lord appeared to them as they were rebelling against God (Mosiah 27:11); in the anguish of his soul over his iniquities Aaron was converted and turned to the service of God.
When his father had no son willing to accept the kingdom, the voice of the people asked that Aaron be made king, but he had gone up to the land of Nephi and declined the throne, choosing to preach to the Lamanites instead (Mosiah 28:10; 29:1-6).
Among the Lamanites Aaron and a number of his brethren were cast into prison at Middoni, where they suffered hunger and bonds until Lamoni and Ammon delivered them (Alma 21:13-14). Led by the Spirit to the land of Nephi, Aaron taught the king who reigned over all the land, the father of Lamoni, beginning from the creation of Adam and moving through the fall and humanity’s carnal state before expounding the plan of redemption, which was prepared from the foundation of the world, through Christ (Alma 22:12-13). The king, moved by Aaron’s teaching, prayed to give away all his sins to know God (Alma 22:18); he and his whole household were converted (Alma 22).
The king sent a proclamation protecting Aaron and his brethren, who went from city to city establishing churches and consecrating priests and teachers, and thousands of Lamanites were converted (Alma 23). Many more were later stirred to remember Aaron’s preaching and converted in the wilderness (Alma 25:6). Aaron rebuked Ammon for boasting in their success (Alma 26:10), was among those Alma took to preach to the Zoramites (Alma 31:6-7), and was named among the brethren whose preaching brought peace and prosperity to the church (Alma 49:30).