In my reading today, I noted a specific date reference in Alma 49 – to the 10th day of the 11th month, to be specific. That was tied to the march of the Lamanite armies under Amalickiah, with their intent to destroy the Nephites plainly present. At the end of the 48th chapter, Mormon notes the lamentations of the Nephites at the prospect of having to kill people in their defense, as such a killing would deprive them of an ability to accept atonement in their lives – which atonement would be focused on in the first 10 days of the new year, leading up to Yom Kippur.
Well, the great lamentations go with the 9th day of the 11th month, Tisha B’Av, a date set by God as a day of Israelite sorrow in the Book of Exodus. It is the date of the destruction of both Solomon’s and Herod’s Temple as well as the extermination of the Bar Kochba Revolt. And here, in the Book of Mormon, there is what seems to be a reference to that day. The armies that enter Nephite territory on the 10th of Av were surely underway on the 9th.
The “why” of all this is that with such a significant date tied to these events, the existential struggle that spans 12 years and 14 chapters in the Book of Mormon narrative comes forward not just as a regrettable war, but as a calamity on the level of the loss of the Temple in Jerusalem. The walls come crashing down, and the people are left exposed to the wrath of an enemy. They will be destroyed in their wickedness, but preserved if they endure the horrors in righteousness.