These verses are also best seen as Moroni’s insertion into the text. They do not follow the style of the text before, nor of what will come after. The use of repetitive resumption for this insertion is more subtle than other examples because the structure of naming the kings makes the connection so much more logical. Moroni leaves his text speaking about Lib, and returns to Lib. (See comments for 1 Nephi 6:1–6 for information on repetitive resumption.)
The purpose of these verses is to describe the Jaredites as a powerful people. They had been promised that they would be a great people, and Moroni wants to make certain that the reader understands that, at least during times when the people were righteous, they were the great people that the Lord had promised them. “And never could be a people more blessed than were they, and more prospered by the hand of the Lord. And they were in a land that was choice above all lands, for the Lord had spoken it” (Ether 10:28).