In 3 Nephi 10:18 we learned that the appearance of the Savior came in the “ending of the thirty and fourth year” from the sign of Christ’s birth. At the beginning of the book of 4 Nephi, Mormon gives us a year count that gives the ending of that year, and then marks the thirty fifth year as well. Mormon had ended his record that we know as 3 Nephi with a commentary on the mission of the twelve selected by the Lord. As he begins this new record, he continues the theme from the last record, and indicates again that the twelve taught and were effective in baptizing many. The book begins with the success of the disciples. At the end of the book, the people are so wicked that the disciples mourn for the sins of the people (see verse 44). This will be a book of contrasts, where the good of the beginning becomes the evil of the ending.
Chronology: The thirty-fourth year would correspond to 31 A.D.
Textual: Mormon treats the book of 4 Nephi as a continuation of the end of 3 Nephi. The original text would certainly have had some continuity of events, but Mormon makes his selection of events for his own purposes. He has ended 3 Nephi with the three Nephites, and he opens 4 Nephi with them.
In the 1830 edition the chapter is simply named, The Book of Nephi with a subtitle indicating: “which is the son of Nephi, one of the disciples of Jesus Christ.” That is the only indication we have of the reason for a name change or of who this particular Nephi might be until we arrive at verse 19 below, when Nephi is finally identified.
Unlike 3 Nephi, which contains large citations from Mormon’s source text, this record has no obvious citations. Mormon is consulting the record, but what we have is a synopsis of the record, not a citation from the text. The connection between this record and the official plates of Nephi is not precisely clear. See the comments following verse 19 below.