Nephi equates the last days with the days when the Lord God would bring forth the records of his people (the Book of Mormon) unto the inhabitants of the earth (v. 14). The last days are those days after the remaining people of their seed (the Lamanites) had dwindled in unbelief and had been smitten by the Gentiles. His prophecies are an explanation of what Isaiah had said about the destruction of his people and the Book of Mormon coming forth.
Nephi paraphrases and comments on the present-day text of Isaiah 29:3–4 (vv. 15–16). Although the Nephite nation will have been destroyed, the righteous among them will have left a record hidden in the ground. This record will come forth as if those people were speaking from the ground. The reference to the “familiar spirit” out of the ground does not mean that the message is comparable to that in the Bible, as is often claimed, which refers to the ancient custom of witchcraft where people who were supposedly familiar with the dead, were able to call them up to speak to the present generation. However, the Nephite message will be written and proclaimed through the power of God and is as a familiar spirit, not witchcraft. The pronoun “him,” to whom will be given “power, that he may whisper concerning them” (v. 16), may be a reference to Joseph Smith.
Writing the things that would be done among them (v. 17) seems to be a direct quotation, but, based upon 2 Nephi 27, Nephi is more likely quoting the original text of the present Isaiah 29, it appears that Nephi is paraphrasing and commenting on what is now 2 Nephi 27:6. He also paraphrases the present Isaiah 29:5 (v. 18), foretelling the sudden destruction of the Nephites. Nephi then prophesies of those who dwindled in unbelief (those we know as Lamanites) being smitten by the Gentiles (v. 19).