The Lord elaborates his assertion from verse 11. Here he specifies that he will speak to both the Jews of the Old World, and the Jews of the New World (the Nephites) and they shall have record of that communication. He notes that he shall also speak to others of his scattered chosen people - and then indicates that he shall speak to all the nations of the earth. The final statement opens the way for the communication of the Lord to the Gentile prophets. The other statements follow the division between Jew and Gentile, with the word of God coming to the Gentile through the mouth of a Jew, whether from the Old World or the New.
This juxtaposition of the Jewish scripture/Gentile world is the thrust of this section. The Gentiles will revile and hate the Jews, but do so contrary to the word that they have received. The Lord very clearly admonishes the Gentiles to be respectful of his chosen people, in contrast to the unfortunate history of the Jewish/Gentile relations in the Old World.
Sociological: This verse marks the earliest presence of the word “Nephite” in the Book of Mormon. Of course it is not the earliest presence of the term in this commentary, for it is a convenient marker for Nephi’s people. It is not the first self-designation of these people, however.
The first name they use is “people of Nephi:”
2 Ne. 5:8
8 And my people would that we should call the name of the place Nephi; wherefore, we did call it Nephi.
9 And all those who were with me did take upon them to call themselves the people of Nephi.
The calling of both place and people by the same name is not unusual, and was a mark of high esteem for the man Nephi. Nevertheless, the original designation was to be called the “people of Nephi” rather than Nephite.
When Jacob is speaking in Nephi’s record, this is also the designation he chooses:
2 Ne. 6:1
1 The words of Jacob, the brother of Nephi, which he spake unto the people of Nephi:
This designation appears to continue in Jacob’s writing as a mode of referring to this grouping of people (Jacob 1:2). Nevertheless, it is Jacob who is the next writer to give us the term “Nephite:”
13 Now the people which were not Lamanites were Nephites; nevertheless, they were called Nephites, Jacobites, Josephites, Zoramites, Lamanites, Lemuelites, and Ishmaelites.
14 But I, Jacob, shall not hereafter distinguish them by these names, but I shall call them Lamanites that seek to destroy the people of Nephi, and those who are friendly to Nephi I shall call Nephites, or the people of Nephi, according to the reigns of the kings.
Jacob notes that the self-named people also have a generalized collective name. In addition to “people of Nephi” which appears to designate a political unit (at least in the beginning) there remained within the political unit kinship units that could be appropriately designated by their clan leader (hence Jacobites, Josephites, Zoramites, etc.) Jacob very specifically includes the Lamanites and Lemuelites as tribal designators. However, by the time Jacob is writing, the major political categories and the tribal categories have consolidated terminologies. Jacob can assert that there are only two collective terms, Lamanite and Nephite, and Jacob places the two in enmity.
In spite of the fact that we don’t have the elucidation of the collective use of the names until Jacob, it is certain that they were used earlier, as “Lamanite” is used earlier in that very context of “enemy” to the people of Nephi:
2 Ne. 5:14
14 And I, Nephi, did take the sword of Laban, and after the manner of it did make many swords, lest by any means the people who were now called Lamanites should come upon us and destroy us; for I knew their hatred towards me and my children and those who were called my people.
Nephi certainly would have understood that among the “Lamanites” there would also have been Lemuelites, but he doesn’t make that distinction. This collective use of the single term for the multiple kinship groups must have begun during Nephi’s lifetime, even if they preferred a designation of “people of Nephi” as their formal name.
In this verse, however, the Lord uses the term Nephite. This is very clearly being used as a collective designation, as it applies to all of those to whom the Lord spoke and who recorded the word of the Lord.