At the end of the last chapter we had a righteous people being preserved by the hand of the Lord. The last chapter may be presented by Mormon as proof of the Lord’s protection upon the righteousness of the people. Mormon wants to show a complete fulfillment of this promise, so here he adds that they have prospered in the land, and that “they became exceedingly rich.” It is interesting that Mormon sees their riches as a fulfillment of the covenant with the Lord. There is nothing inherently wrong about the riches themselves. However, as we have seen in the past, the Nephite acquisition of riches leads to the increase in the other cultural trappings that come along with their form of riches, and we will be seeing the virtually inevitable internal tensions that will arise as the people desire for more of the world that comes with these riches.
Textual: Mormon cites the foundational promise of the Nephite people. We have this promise from Lehi himself in 2 Nephi 1:9 and 2 Nephi 4:4. Nephi cites the promise in 1 Nephi 2:20 and 1 Nephi 4:14. Alma cites this promise in Alma 9:13, Alma 36:1, and Alma 38:1. This is easily the most cited of the purely Nephite scriptures, and rightly so as it is the original promise of the Lord to the descendants of Lehi.