Alma 24:28–30

Now the greatest number of those of the Lamanites who slew so many of their brethren were Amalekites and Amulonites, the greatest number of whom were after the order of the Nehors. Now, among those who joined the people of the Lord, there were none who were Amalekites or Amulonites, or who were of the order of Nehor, but they were actual descendants of Laman and Lemuel.

And thus we can plainly discern, that after a people have been once enlightened by the Spirit of God, and have had great knowledge of things pertaining to righteousness, and then have fallen away into sin and transgression, they become more hardened, and thus their state becomes worse than though they had never known these things.

From section: Unbelieving Citizen Revolt, Attack and Conversion

From page: Mission to the Lamanites