Mormon still returns to his primary interest, the “seed of this people.” At this point, Mormon repeats the cultural statement that defines the comparison between Lamanite and Nephite, between bad and good in the Nephite vocabulary. The righteous who are “white and delightsome” are becoming unrighteous, or “dark and loathsome.” There is no missing the point that these two phrases are intentionally opposite. They are meant to describe opposite conditions.
What Mormon also tells us is that the way in which his people will survive to the time of the coming of the Book of Mormon is becoming in every way like the Lamanites around them. They will adopt all of their culture, including “their unbelief and idolatry.” While that statement specifically defines the current Nephites, it is indicative of the ways in which the Nephites have already become just like their enemies.
[beyond the description of that which ever hath been amongst us]: This is a statement that appears to be quite similar to common statements from virtually every period of man’s history, that we are more wicked now than we have ever been. Mormon is stating that his descendant Nephites-become-Lamanites will become even more wicked. While this may be read as a generic statement, it is also possible to read this statement in the context of Mormon’s times. We have already seen that there are two types of innovations happening in Mormon’s world that we have not seen before. There is a war of destruction that will actually burn enemy cities, and there is the sacrifice of women and children that is apparently so new and appalling that Mormon comments upon it specifically. It is therefore very tempting to have this Mormon witnessing the transformation of his land and culture under the imported threat of the Central Mexicans from Teotihucan with their newly imported ideas, and Mormon understanding that those Teotihuacanos represent the world into which his descendants will pass. It would be no wonder that he would see their future as “beyond the description of that which ever hath been amongst us.”