Jacob 3

Jacob 3:3 But, wo, wo, unto you that are not pure in heart, that are filthy this day before God; for except ye repent the land is cursed for your sakes; and the Lamanites, which are not filthy like unto you, nevertheless they are cursed with a sore cursing, shall scourge you even unto destruction. this is an interesting theme throughout the bookof Mormon: the Nephites will be scourgedby the Lamanites because they sin, knowing the will of God, which is worse than just sinning. If there really were two constant groups of people throughout, one that knew the will of God and another that never knew it, this would be a solid and reliable theme. However, whe there is a fairly constant now ledge of God among the Nephites, there are period forays into knowledge made by the Lamanites, particularly as time progresses. E.g. Samuel was a Lamanites because at that time, the Lamanites were the righteous people. After Christ, everybody alive was a Nephite, and the curse was lifted. The trick, it would seem, to not having your children wiped off the face of the earth is not righteousness, but early adoption of wickedness. (I'm sure there's some reason why that is flawed, but it's not coming to me right now.)