The missionary journeys of the sons of Mosiah among the Lamanites between approximately 90 BC and 77 BC brought many thousands into the fold of Christ, including the households of King Lamoni in the land of Ishmael and of his father, king over all the Lamanite lands. Mormon characterized the strength of their commitment: “I say unto you, as the Lord liveth, as many of the Lamanites as believed in their preaching, and were converted unto the Lord, never did fall away”.
So firm was their resolve to place their wicked deeds behind them that they abandoned their weapons and swore an oath never again to take them up. Assuming the new name of Anti-Nephi-Lehies to distinguish themselves from their former brethren , these people became industrious and prosperous, cultivating dealings with the Nephites. When the Lamanites came up against the Anti-Nephi-Lehies to slay them, the people remained firm in the commitment they had made to the Lord.
Now when the people saw that they were coming against them they went out to meet them, and prostrated themselves before them to the earth, and began to call on the name of the Lord; and thus they were in this attitude when the Lamanites began to fall upon them, and began to slay them with the sword.
Now when the Lamanites saw that their brethren would not flee from the sword, neither would they turn aside to the right hand or to the left, but that they would lie down and perish, and praised God even in the very act of perishing under the sword—
Now when the Lamanites saw this they did forbear from slaying them; and there were many whose hearts had swollen in them for those of their brethren who had fallen under the sword, for they repented of the things which they had done.
As a result, the ranks of the Anti-Nephi-Lehies were increased by over a thousand new converts—more than the number who were killed in the attack. In the ongoing battle with the Nephites, other Lamanites also joined with the Anti-Nephi-Lehies. For the protection of these followers of God, the Lord commanded Ammon to lead them out of the Lamanite territories and northward to safety. They were readily accepted by the Nephites and given their own territory in the land of Jershon around 77 BC. There they were known by the Nephites as “the people of Ammon”.
When the conflict between the Nephites and the Lamanites once again became severe, the people of Ammon were tempted to abandon their oath and take up weapons in defense of freedom. Helaman dissuaded them. “I would not suffer them that they should break this covenant which they had made, supposing that God would strengthen us, insomuch that we should not suffer more because of the fulfilling the oath which they had taken”. God strengthened the cause of freedom, for it was the sons of the people of Ammon who rose up as the army of Helaman—the 2,000.
The parents of these faithful warriors sent them provisions at a crucial point in their campaign in the year 65 BC , and victory was achieved. Several years later, some 4,000 additional Lamanites entered a covenant to abandon their weapons of war and joined with the people of Ammon at Jershon. Many of the Lamanite prisoners of war followed suit, for they “were desirous to join the people of Ammon and become a free people”. Many of the people of Ammon participated in the major migration northward in the year 46 BC.