Alma 3:6–10 is a conceptual unit that shows a dramatic affinity to 2 Nephi 5:20–23:
Wherefore, the word of the Lord was fulfilled which he spake unto me, saying that: Inasmuch as they will not hearken unto thy words they shall be cut off from the presence of the Lord. And behold, they were cut off from his presence.
And he had caused the cursing to come upon them, yea, even a sore cursing, because of their iniquity. For behold, they had hardened their hearts against him, that they had become like unto a flint; wherefore, as they were white, and exceedingly fair and delightsome, that they might not be enticing unto my people the Lord God did cause a skin of blackness to come upon them.
And thus saith the Lord God: I will cause that they shall be loathsome unto thy people, save they shall repent of their iniquities.
And cursed shall be the seed of him that mixeth with their seed; for they shall be cursed even with the same cursing. And the Lord spake it, and it was done.
While the language is not identical, the repetition of themes suggests a dependence between the text in Alma and that in 2 Nephi. Because the Alma text comes from the large plates and 2 Nephi is on the small plates, probably the dependence is not direct. It seems likely that Alma is repeating a standard definition that developed early and continued in both written and oral traditions.
Alma 3:6 introduces the main elements of the curse (dark skin) on the Lamanites because of their rebellion against Nephi. 2 Nephi 5 begins with this same concept. (See commentary accompanying 2 Nephi 5:21 for an analysis of the curse and issues of skin color.)