Lamoni was a Lamanite king over the land of Ishmael and a descendant of Ishmael (Alma 17:21). When Ammon, one of the sons of Mosiah, asked to live among his people, Lamoni offered him one of his daughters in marriage; Ammon declined and instead became a servant set to watch the king’s flocks (Alma 17:24-25). At the water of Sebus, marauders scattered the flocks, and Ammon drove them off, slaying their leader and cutting off the arms of those who attacked him (Alma 17:34-38). On hearing of it, Lamoni concluded that Ammon was the Great Spirit (Alma 18:9-11).
Ammon used the occasion to teach Lamoni about God, the creation of the world, and the plan of redemption (Alma 18:24-40). Lamoni believed his words and fell to the earth as if dead, where he lay for two days and two nights while his household mourned (Alma 18:42-43). Ammon knew the king was under the power of God, his unbelief being cast away (Alma 19:6).
When Lamoni rose, he testified that he had seen his Redeemer, who would be born of a woman and redeem all who believe on his name; he then sank down again with joy, and the queen sank with him (Alma 19:13). Many of the people believed and were baptized, and a church was established among them (Alma 19:35).
Traveling with Ammon to the land of Middoni to free Ammon’s imprisoned brethren, Lamoni met his father, the king over all the Lamanite land, who was angry that his son associated with a Nephite and commanded him to slay Ammon. Lamoni refused; his father drew his sword against him, and Ammon intervened, withstanding the king’s blows and disarming him until the king agreed to release the prisoners and let Lamoni keep his kingdom (Alma 20:8-26). The father was later taught by Aaron and his whole household was converted (Alma 22:23). Lamoni’s people were among the Lamanites who were converted across several lands and cities (Alma 23:8-13). Having been converted, they would not take up arms against their brethren, and Lamoni commanded them likewise; they buried their weapons of war deep in the earth rather than shed blood again (Alma 24:6-17).