As already commented on, the Lamanites were a moral people, which was the reason they were not destroyed (v. 5). Their becoming a blessed people is promised repeatedly in the Book of Mormon (see 1 Nephi 15:14; 2 Nephi 30:4–6; Alma 9:16–17; Helaman 15:10–13; Mormon 5:19–20 and others). Although the Book of Mormon teaches of their being marked with a dark skin, it certainly does not teach any prejudice or inequality because of it. The mark was given “that they might not be enticing unto my people” (2 Nephi 5:21). Association with wickedness affects behavior. As Paul admonished: “Abstain from all appearance of evil” (2 Thessalonians 5:22).
The pains of hell, Alma later said, was: “the memory of my sins … there could be nothing so exquisite and so bitter as were my pain.” They can only be permanently removed by the Atonement of Christ (Alma 36:19–21).
The second death was described by Samuel the Lamanite:
17 But behold, the resurrection of Christ redeemeth mankind, yea, even all mankind, and bringeth them back into the presence of the Lord.
18 Yea, and it bringeth to pass the condition of repentance, that whosoever repenteth the same is not hewn down and cast into the fire; but whosoever repenteth not is hewn down and cast into the fire; and there cometh upon them again a spiritual death, yea, a second death, for they are cut off again as to things pertaining to righteousness. [Helaman 14:17–18]