Firm and steadfast and immovable

I have noticed before that Mormon sometimes alludes to a previous statement or theme in the Book of Mormon when describing something in his abridgment. Notice how he describes a group of Lamanite converts

in the thirtieth year the church was broken up in all the land save it were among a few of the Lamanites who were converted unto the true faith; and they would not depart from it, for they were firm, and steadfast, and immovable, willing with all diligence to keep the commandments of the Lord. (3 Nephi 6:14)

Just reading how Mormon characterizes these descendants of Laman and Lemuel makes me impressed by them. But Mormon also seems to create a couple of interesting references. Compare with 1 Nephi 2:10, where Lehi speaks to Lemuel

And he also spake unto Lemuel: O that thou mightest be like unto this valley, firm and steadfast, and immovable in keeping the commandments of the Lord!

(As a side note, see this article on Lehi's use of desert poetry).

In 2 Nephi 4:5, Lehi speaks to the children of Laman (and later gives the same blessing to the children of Lemuel)

for behold, I know that if ye are brought up in the way ye should go ye will not depart from it.

Lehi wished that Lemuel were "firm and steadfast and immovable", but instead, he and his brother taught their children to hate the Nephites (See Mosiah 10:17). But Lehi blessed their children knowing that "their hatred is because of the iniquity of their fathers" (Jacob 3:7) and if they were taught differently, they would not depart from the truth. 

See what Mormon is doing in 3 Nephi 6? He knew about these promises and when describing a group of Lamanites that had been taught "the true faith" and become converted, he demonstrated this principle in practice by referring to these statements on the small plates of Nephi. He described the Lamanite converts as becoming like the valley of Lemuel and receiving the promises given to the children of Laman.