Isaiah's characterization of his audience continues, contrasting their righteous claims with the reality of their actions. This should certainly speak a warning to modern members of the house of Israel as it is represented in the Restoration of the Gospel to make sure that we do not fall into the same trap as those of old. It is all too easy for the Latter-day Saints to also assume that because we belong to a religion with a prophet that we therefore follow the prophet. That because we have ancestors who walked over the long trail to Utah that we therefore are also on the right trail. Isaiah calls to us as easily as he called to his contemporaries.
Application to the Nephi's audience: At the time Nephi is giving this sermon, the split between Lamanites and Nephites has not yet occurred. In the context of Lehi's at times contentious family, these words are also particularly apt. Laman and Lemuel know and revere their heritage, even when they are denying the spiritual power of their father and brother.