Embedded in the opening chapters of Nephi's account is another remarkable testament of his ability to record accurate, real-world geographical facts. As a native of Jerusalem, Nephi knew first-hand that travel from the city in the Judean mountains in any direction literally meant going "down from" it; and that to travel to Jerusalem was to "go up." Jerusalem's elevated geography is further, uniquely accentuated by the huge Wadi Arabah to its east, containing the Dead Sea, some 1,300 feet below sea-level. In no less than 25 instances, Nephi's first-hand record correctly uses the terms is the same manner that biblical writers also did when discussing the various travels of the family to and from Jerusalem.
Significantly, though, this convention was not continued in the Book of Mormon by later authors and editors. While they likely knew that Jerusalem was situated in mountains, that knowledge had less impact and relevance to those who had not personally experienced the topography of the Holy City themselves. Writing years later in the New World, Nephi himself adapted his terminology to suit, as when he prophesied of a distant day when his descendants would be taught "that we came out from Jerusalem" (2 Nephi 30:4). In this context, speaking of the gradient leading down from Jerusalem or the directions travelled- another point of consistency - would be simply superfluous; unnecessary detail when addressing people who never knew Jerusalem first-hand.
We also find that topographical statements concerning Jerusalem are completely absent from Nephi's brief introduction to the First Book of Nephi. Although it mentions the initial exodus from Jerusalem twice, and the return of Lehi's sons to obtain the records of Laban, there are no qualifying terms referencing geography. It was simply unnecessary detail in a summary. Later writers in the Book of Mormon were not unaware of the term to "go up." In Mosiah 10:10, for example, Zeniff uses the term three times when describing a battle against the Lamanites. Yet, just two verses later (vs. 12), when referring back to the original departure from Jerusalem, there is no "down from" attached to it. This consistency is a striking affirmation of both multiple authorship and of the record's historicity. (Warren P. Aston, Lehi and Sariah in Arabia: The Old World Setting of the Book of Mormon [2015], location 984 of 6942 of Kindle ed.)