Historical: Nephi reinforces his personal testimony of the true Messiah by referencing his sources. He knows that the Messiah is to come, and knows that it is to be 600 years from the time his father left Jerusalem. This dating is either a general round number (which is perfectly acceptable in prophetic declaration) or it may be an indication that the nature of a year in the counting of the New World Nephites differed from the Old World.
Randall P. Spackman has done some interesting work on this prophecy of 600 years:
"In counting and recording the passage of time for hundreds of years, Lehi’s descendants obviously used some type of calendar accurately. We are led to ask what kind of calendar they used because dates derived from well-attested external history establish a time window several years too small to allow for the full 600 years stipulated in Lehi’s prophecy. Did Lehi mean that the Savior would come in about 600 years, or must we look elsewhere for an explanation?
Evidently, Lehi was not simply approximating the time of the Lord’s birth, because the Book of Mormon records tat the heavenly signs marking that event appeared after the passage of an even 600 years - that is, in the 601st year, matching the prophesied time frame with precision (see 3 Nephi 1:4, 21, 26). This brings us back to the Nephite calendar, which was surely quite different from our modern method of reckoning time, and a crucial question arises: How long was a Nephite year?“ (Spackman, Randall P. ”The Jewish/Nephite Lunar Calendar." In: Journal of Book of Mormon Studies, 1998, 7:1:50)
After discussing the external evidence requiring the foreshortened year count, he concludes:
“If the Nephites measured the 600-year period preceding Christ’s birth with a lunar calendar composed of twelve ”moons,“ there is no discrepancy at all in the counting of 600 years. A twelve-moon calendar averages only 354.365 days per year, eleven days fewer than a solar calendar, which averages 365.2422 days per year. Between 597 BC and 5 BC, ample time existed for this lunar calendar to measure all 600 years.” (Spackman 1998, p. 51.)
Translation: Most problematic for modern readers is the final assertion of Nephi: “according to the words of the prophets, and also the word of the angel of God, his name shall be Jesus Christ, the Son of God.” Most particularly problematic is the specific declaration of the name. It certainly is no problem for a prophet to know a future name, for Nephi names Mary as Jesus’ mother (1 Nephi....). The problem is in the conflation of name and title that occurs with “Jesus Christ.” Jesus is the proper name. Christ is the title, and a title that is derived from the Greek translation of the Hebrew meaning of “Messiah.”
Edward Brandt examined this question and noted that verse 19 contains “both the English transliteration of the Hebrew term for ”the anointed one“ - Messiah - and also the transliteration of the Greek term extended to the English for ”the anointed one“ - Christ.” (Brandt, Edward J. “The Name Jesus Christ Revealed to the Nephites.” In: Second Nephi, The Doctrinal Structure. Religious Studies Center, BYU, 1989, p. 203.) He therefore recognizes the problem as stated. His answer, however, is off the mark:
“The continued use of the name Jesus Christ in the Book of Mormon, in view of all of the other names and titles used in the scriptures, shows it had an important influence on the Nephites throughout their history” (Brandt 1989, p. 203). His argument is to show that “Christ” is used frequently, and is associated with the “name.” For instance, he cites Mosiah 15:21 (Brandt 1989, p. 204).
The text of that verse is:
Mosiah 15:21And there cometh a resurrection, even a first resurrection; yea, even a resurrection of those that have been, and who are, and who shall be, even until the resurrection of Christ—for so shall he be called.
Brandt’s analysis emphasizes the “for so shall he be called” as a justification for the use of the term Christ in the declaration. He concludes: “They knew as Peter knew that there was no ”other name given under heaven save it be this Jesus Christ,…whereby man can be saved" (2 Nephi 25:20; compare Acts 4:12; see also 2 Nephi 31:20-21; Mosiah 3:17; 5:8; D&C 18:23; Moses 6:52,57) (Brandt 1989, p. 205).
It is instructive to view the referenced verse in Acts 4:12:
12 Neither is there salvation in any other: for there is none other name under heaven given among men, whereby we must be saved.
The sentiment is clearly the same, but there is a significant difference. While the emphasis on name remains, it is only in the Book of Mormon that Jesus Christ is used as a name rather than a name and title (the only possible explanation for the presence of Messiah and Christ in the same sentence. Brandt is answering the wrong question. He is suggesting that Christ is a known title, and so it was. That does not mean, however, that Christ is an ancient word and not a transliteration of Greek. In all of his texts, the term Messiah fits equally as well. The difference is that Joseph as a translator preferred the more familiar “Christ.”
Brandt’s arguments never answer nor address the reason for the dual presence of Messiah and Christ, unless Brandt suggests that “Christ” is a personal name and not a title. That might answer the question, but it raises too many others. Why would Jesus have a last name in the New World, but not in the Old World. Why would Jesus be the only person in the entire Book of Mormon to have a last name? Why would his “last name” be the same as his title, but only seen through a Greek transliteration rather than a Hebrew one?
We have in this passage another evidence of the nature of Joseph’s participation in the creation of the text. His own probable confusion between the titles, or at the very least, his much greater familiarity and comfort with Christ is the reason for the introduction of the term, not an imagined revealed name of “Christ.”