These verses redefine who are Lamanites and Nephites. Previously in the Book of Mormon, the division was a racial one. With the experience of the followers of Amlici, it became clear to the Nephites that their enemies could come from within. Therefore, the definition of Lamanites and Nephites changed. The distinction now becomes primarily religious. Those who believe in Lamanite traditions, whether of Nephite or Lamanite descent, are called Lamanites. Those who believe in the God of the Nephites, whether light skinned or dark skinned, are considered Nephites. This remains the pattern for the rest of the Book of Mormon. This religious definition can be seen again after the Savior’s ministry and the peace which followed. About 194 AD, a small part of the people…had revolted from the church and taken upon them the name of Lamanites; therefore there began to be Lamanites again in the land (4 Nephi 1:20, italics added).
“Originally, the Lamanites were the children of Laman, Lemuel, and some of the family of Ishmael; but as the centuries passed there were many defections in both nations, when the dissatisfied would join the opposing race and affiliate and intermix with them, so that the two names at last became more an indication of religion and civilization than of birth.” (George Reynolds, A Complete Concordance of the Book of Mormon, p. 395 as taken from Latter-day Commentary on the Book of Mormon compiled by K. Douglas Bassett, p. 248)