The Lamanites provided an object lesson for the people of Ammonihah of a people who had not kept the commandments of God (v. 14). They had been cut off from the Lord’s presence for not keeping the commandments of God, but they had been a moral people and so had not been destroyed (see Jacob 3:5–7). Furthermore, the Lamanites of Alma’s day had been kept in ignorance of the gospel principles because of the traditions of their fathers (Alma 9:15–16). Therefore, the Lord had visited “the iniquities of the fathers upon the children unto the third and fourth generation of them that hate [God]” (Mosiah 13:13). This law of the Lord is the natural effect of traditions that are handed down from one generation to another. It usually takes about three or four generations to overcome those traditions. The Lord has verified this law (the 2 of the 10 commandments, see Exodus 20:40) in modern revelation.
38 Every spirit of man was innocent in the beginning; and God having redeemed man from the fall, men became again, in their infant state, innocent before God.
39 And that wicked one cometh and taketh away light and truth, through disobedience, from the children of men, and because of the traditions of men.
40 But I have commanded you to bring up your children in light and truth. [D&C 93:38–40; italics added]
The Lord, however, judges his people on the basis of what they have been given. Therefore, every man will be accountable for their own sins and not for the sins and transgressions of an ancestor or parent (see Article of Faith 2). When the Lamanites are brought to believe in the Lord’s word (Alma 9:17), he will show “mercy unto thousands of [generations] that love [God] and keep [his] commandments” (Mosiah 13:14; Exodus 20:5). The many promises extended to the Lamanites (Alma 9:16) are blessings of the gospel of Jesus Christ. Today these blessings are rapidly spreading among the Lamanite people.