According to Reynolds and Sjodahl, special attention is called to the phrase “the book of Moses” (1 Nephi 19:23). Why does not Nephi say, “The books of Moses”? Or, even, “The five books of Moses” (see 1 Nephi 5:11)? For the simple reason that, to the Jews of his day, what we know as the five books of Moses were one volume [or scroll] which they called, “the Law,” (Torah). [George Reynolds and Janne M. Sjodahl, Commentary on the Book of Mormon, Vol. 1, p. 205] [But see the commentary on 1 Nephi 5:17 for the idea that the Nephite plates were patterned after the brass plates--that the writings of each prophet or record keeper were assembled into one book.] [See also the commentary on 1 Nephi 3:3]
[1 Nephi 19:23]: That I Might More Fully Persuade Them to Believe in the Lord Their Redeemer I Did Read unto Them That Which Was Written by the Prophet Isaiah:
In chapters 20 and 21, Nephi will include in his writings what has come to correspond to chapters 48 and 49 of Isaiah. One might ask, Why did Nephi include these writings at this point in his record? Let us first review what Nephi himself had to say. In 1 Nephi 19:21-24 we find the following:
[The Lord] surely did show unto the prophets of old all things concerning them; and also he did show unto many concerning us; wherefore, it must needs be that we know concerning them for they are written upon the plates of brass.
Now it came to pass that I, Nephi, did teach my brethren these things; and it came to pass that I did read many things to them, which were engraven upon the plates of brass, that they might know concerning the doings of the Lord in other lands, among people of old.
And I did read many things unto them which were written in the book of Moses; but that I might more fully persuade them to believe in the Lord their Redeemer I did read unto them that which was written by the prophet Isaiah; for I did liken all scriptures unto us, that it might be for our profit and learning … that [we] may have hope.
According to Kent Brown, Nephi assures us that Isaiah had been one of his favorite books, and his acquaintance with this work had led him to quote significant parts of it (e.g., 1 Nephi 19:23; see also 2 Nephi 11:8). Moreover, Nephi supplies us with his reasons--public reasons, it turns out--why he had included chapters 48 and 49 of Isaiah at the end of his first book.
To be sure, the public reasons that Nephi offers to us for his appeal to Isaiah stand within the larger prophetic message about the scattering and gathering of Israel, of which he and his family--the scattered--and their distant posterity--the gathered--were a part. One does not look far to find that Isaiah’s prophecies had a good deal to say about these events.
However, multiple passages plainly point to aspects of the journey of Lehi’s family. One might note that in Nephi’s entire trip, from beginning to end, starting with the flight from Jerusalem and ending with the settlement in the promised land. In a word, Nephi is saying, “Isaiah spoke about us.” For example, Nephi, if not others, must have taken courage from the Lord’s assurance that he “leadeth thee by the way thou shouldst go” and that those who trust in him “thirsted not” because “he led them through the deserts” and “caused the waters to flow out of the rock for them” (1 Nephi 20:17, 21 = Isaiah 48:17, 21). Moreover--continuing the desert imagery--“They shall not hunger nor thirst; neither shall the heat nor the sun smite them: for he that hath mercy on them shall lead them, even by the springs of water shall he guide them” (Isaiah 49:10 = 1 Nephi 21:10). Plainly, one can identify a number of passages that naturally would have spoken to the situation of the family while traveling through Arabia.
This situation becomes evident in words of Isaiah about a river and the sea, recalling both that Lehi named a river after his son Laman and that the Red Sea, into which the river flowed, was one of the major geographical features near the first camp (1 Nephi 2:5, 8-9). In addition, on the far side of the Arabian desert the sea formed both a barrier as well as a highway of sorts to the promised land (1 Nephi 17:5-6; 18:8, 23). Isaiah wrote, “O that thou hadst hearkened to my commandments! then had thy peace been as a river, and thy righteousness as the waves of the sea” (Isaiah 48:18 = 1 Nephi 20:18). Lehi spoke similar words to Laman at the time he named the river after him: “O that thou mightest be like unto this river, continually running into the fountain of all righteousness!” (1 Nephi 2:9). In sum, Nephi‘s record of Lehi’s words to his wayward sons, both at the departure from Jerusalem and in the New World, brims with allusions to words from Isaiah 48-49.
The deep, at times terrible, impact that the desert trek made in the soul and memory of Nephi, can be seen in his choice of Isaiah passages that follow the narrative of his family’s trip to the land of promise. Understanding that Nephi saw Isaiah as one who had been shown matters “concerning us” (1 Nephi 19:21), a number of possible allusions to the family’s journey stand in chapters 48 and 49. These passages have to do with flight, next with difficulties in a desert clime, and then to passages which bring assurance of the Lord’s aid.
Nevertheless, in introducing chapters 20 and 21 (Isaiah 48 & 49), Nephi announces that his most important purpose--and I want to emphasize this purpose--is to “more fully persuade [his people] to believe in the Lord their Redeemer” (1 Nephi 19:23). Consistent with his first purpose of bringing others “to believe in the Lord,” one observes that embedded in Isaiah 49 lies a clear prophecy about the future Messiah-king, portrayed as the “servant of the Lord” (Isaiah 49:1-6 = 1 Nephi 21:1-6).
Another reason that Nephi included Isaiah’s prophecies here in 1 Nephi appears to be “for our profit and learning” (1 Nephi 19:23). It seems that along with this learning, Nephi expected Isaiah’s teachings to give his people “hope” (1 Nephi 19:24).
As a parting comment, Brown exhorts the Book of Mormon reader to observe from every nuance how thoroughly Nephi is acquainted with Isaiah, for Nephi’s knowledge seems beyond challenge. Throughout his work, Nephi’s expressions brighten with phrases and terms that reflect an influence radiating from Isaiah. [S. Kent Brown, “What Is Isaiah Doing in First Nephi?,” in From Jerusalem to Zarahemla: Literary and Historical Studies of the Book of Mormon, 1998, pp. 9-12, 17-19]