FairMormon is a non-profit organization dedicated to providing well-documented answers to criticisms of LDS doctrine, belief and practice.
Source:Chadwick:Glimpses of Lehi's Jerusalem:Lehi's House at Jerusalem and the Land of His Inheritance:Going "up" to Jerusalem
Chadwick: "one always went 'up' to come to the Jerusalem region, and one always went 'down' when exiting the Jerusalem region"
Jeffrey R. Chadwick: 
These observations are demonstrated by a three-step examination of Nephi's text: Nephi and his brothers returned from the valley of Lemuel up to the land of Jerusalem (1 Nephi 3:9). They then went down to the land of inheritance to collect Lehi's gold and silver (1 Nephi 3:16, 22). Finally, Nephi and his brothers returned back up again to Jerusalem (1 Nephi 3:23). It is important to remember that in the idiom of Nephi one always went up to come to the Jerusalem region, and one always went down when exiting the Jerusalem region. This is also the Hebrew idiom employed in the Bible, where persons in both the Old and New Testaments typically are said to go down to leave Jerusalem (see, for example, 2 Samuel 5:17; Luke 10:30; and Acts 8:15) and go up to come to Jerusalem (see, for example, 2 Chronicles 2:16 and Matthew 20:18). Nephi adhered to this Hebrew idiom throughout his account—whenever his party is reported to have gone to Jerusalem, they went up (see 1 Nephi 3:9; 4:4; 5:6; 7:3–4), and whenever the reference is to leaving the Jerusalem region, they went down (see 1 Nephi 2:5; 3:4, 16, 22; 4:35; 5:1; 7:2, 5).
- Jeffrey R. Chadwick, "Lehi's House at Jerusalem and the Land of His Inheritance," Glimpses of Lehi's Jerusalem (Neal A. Maxwell Institute, 2004)