In 1 Nephi 10:8 we find a prophecy, which also occurs in Isaiah 40:3-5, about one who would cry in the wilderness: Prepare ye the way of the Lord. However, there are some words that Nephi records of Lehi's vision that have been criticized because they seem to come exclusively from the New Testament. In 1 Nephi 10:8 we find the following:
"for there standeth one among you whom ye know not; and he is mightier than I, whose shoe's latchet I am not worthy to unloose."
While in Luke 3:16 we read:
"John answered, saying unto them all, I indeed baptize you with water; but one mightier than I cometh, the latchet of whose shoes I am not worthy to unloose; he shall baptize you with he Holy Ghost and with fire."
Thus the critics claim that Joseph Smith plagiarized the Bible in constructing the Book of Mormon.
While it is not readily apparent where these scriptural details came from, there are a number of logical explanations:
(1) Both Nephi and Lehi saw the same vision of the future. If that vision was detailed enough, they could have actually seen and heard John speak those words. In fact, those specific words might have been considered John's own prophecy. To this critics will cry "Foul!" How could John be speaking King James English? However, they fail to understand the process of revelation. Joseph Smith was inspired to translate in the style and composition of the day.
(2) There might have been more to the words of Isaiah on the brass plates than what was later conveyed to the King James Bible. Robert Millet says the following:
Let me say that I am convinced, after years of study, that the closest approximation you and I have to the brass plates, that is, one of the best ways we can get close to understanding what was on the brass plates, is Joseph Smith's translation of the Bible. If you want to know what was there beyond what is obviously in the Book of Mormon, look at the Joseph Smith Translation. (Robert L. Millet, "The Prophets of the Brass Plates," Video Transcript, FARMS, 1996, pp. 7-8; see also the commentary on Helaman 8:17)
(3) The words which are attributed to John might have come from prophecies of other ancient prophets not recorded in the King James Bible nor the Book of Mormon. Robert Millet writes that "there is a pattern among the Nephites as to how they preach the gospel. The great teachers in the Book of Mormon always do it a certain way. They stand up, introduce the subject, then they go back and cite the ancient prophets, and then they bear their own witness" (Millet, "The Prophets of the Brass Plates," pp. 10-11) So John could have been using ancient prophetic words to establish the validity of Christ. As to who originally spoke these words we have no record, however the Book of Mormon records that there were many who wrote concerning Christ (and presumably John):
Yea, the God of Abraham, and of Isaac, and the God of Jacob, yieldeth himself, according to the words of the angel, as a man, into the hands of wicked men, to be lifted up, according to the words of Zenock, and to be crucified, according to the words of Neum, and to be buried in a sepulcher, according to the words of Zenos, which he spake concerning the three days of darkness, which should be a sign given of his death unto those who should inhabit the isles of the sea, more especially given unto those who are of the house of Israel. (1 Nephi 19:10; see also Alma 33:15; 34:7; Helaman 8:20; 3 Nephi 10:16)
(4) As a final note, the reader should be aware that this particular section of First Nephi lies at the heart of a complete chiastic structure testifying that Jesus is the Christ, the Eternal God. In doing so it overlaps the testimonies of Lehi and Nephi, and Isaiah, and presumably other prophets who have gone before them, (and in John's case, perhaps after them). Could they be doing this that perhaps we might "know what great things the Lord has done for their fathers; and that [we] may know the covenants of the Lord, that [we are not cast off forever" (Title Page, Book of Mormon)?
[Alan C. Miner, Personal Notes]