Geography: Ammonihah had earlier been the target of a Lamanite raid after the expulsion of the Anti-Nephi-Lehies from the land of Nephi. (See commentary accompanying Alma 25:1.) I argued there that the Lamanites chose this target opportunistically. Even though it was in northerly Nephite territory, it was approachable by a march up the shore, avoiding other Nephite cities. Apparently this route and the first successful raid motivated the Lamanites to make it a target again.
On this geographical point, Sorenson suggests:
Around 80 B.C. just after Alma’s experience there, “the Lamanites had come in upon the wilderness side, into the borders of the land, even into the city of Ammonihah” (Alma 16:2) and destroyed it. Nine years later they came in by the same route, expecting easy pickings against the partially rebuilt city (Alma 49:1–3). In both cases, it is clear, the Lamanite force had journeyed from the land of Nephi northward along the coastal wilderness strip “on the west of Zarahemla” (Alma 22:28); the Nephites never defended that zone, it seems (they probably never even occupied it seriously, for their record mentions no settlement, no event there). When the attackers got far enough northward, they “went over into the borders of the land of Zarahemla, and fell upon the people who were in the land of Ammonihah” (Alma 25:2). The “over” is precisely correct, for they would have had to cross the western wilderness chain of mountains from the coast to get to Ammonihah, the first major city they came to on the main route.… The fit of text to terrain would be difficult to improve.
Culture: The Nephites used at least three divisions for calculating time: the year, month, and day. The text refers to both months and days by numbers but never as having names.
The Nephites may have used a seven-day week, although the evidence is limited, especially since we are reading a translated text whose translator was familiar only with a seven-day week. The brass plates certainly recorded the seven days of creation that underlay the Israelite seven-day week. Mosiah2 knew of the seven-day week from that source (if nowhere else) because he references it in his reprise of the Ten Commandments:
Six days shalt thou labor, and do all thy work;
But the seventh day, the sabbath of the Lord thy God, thou shalt not do any work, thou, nor thy son, nor thy daughter, thy man-servant, nor thy maid-servant, nor thy cattle, nor thy stranger that is within thy gates. (Mosiah 13:17–18)
“Week” appears three more times in the Book of Mormon:
And there was one day in every week that was set apart that they should gather themselves together to teach the people, and to worship the Lord their God, and also, as often as it was in their power, to assemble themselves together. (Mosiah 18:25)
Now, when they had come into the land, behold, to their astonishment they found that the Zoramites had built synagogues, and that they did gather themselves together on one day of the week, which day they did call the day of the Lord; and they did worship after a manner which Alma and his brethren had never beheld; (Alma 31:12)
And moreover, I would ask, do ye suppose that ye must not worship God only once in a week? (Alma 32:11)
Two of the three “weeks” thus refer to a practice of the apostate Zoramites. However, the concept of meeting once a “week” to worship Yahweh is really a Nephite tradition, since we see it in the book of Mosiah as well.
Does “week” in the Book of Mormon mean the same thing to the Nephites as it does to us? It certainly could, since the Western calendar of the seven-day week is also derived from the same source the Nephites used: the Old Testament. True, competing calendars from the larger society might have replaced the traditional Israelite week, but the evidence is negative. The number “seven” apparently has no significance in the Book of Mormon while the seven creative periods of the Old Testament fostered a large number of symbolic references in Israelite culture. A computer search of the Old or New Testaments for “seven” or “seventh” yields 656 items, most of them symbolic rather than actual enumerations. In contrast, the Book of Mormon yields only seven. Apparently “seven” as a symbol did not make the transition from the Old World to the New.
It should be considered, however, that the Book of Mormon is generally lacking in symbolic numbers. Most numbers appear as physical enumerations, although, as I have argued, “four” and “five,” which are important symbols in Mesoamerica, are exceptions. (See commentary accompanying Mosiah 7:2 and Alma 24:22.)