Alma 16:1-2

1 And it came to pass in the eleventh year of the reign of the judges over the people of Nephi, on the fifth day of the second month, there having been much peace in the land of Zarahemla, there having been no wars nor contentions for a certain number of years, even until the fifth day of the second month in the eleventh year, there was a cry of war heard throughout the land.

2 For behold, the armies of the Lamanites had come in upon the wilderness side, into the borders of the land, even into the city of Ammonihah, and began to slay the people and destroy the city.

God always keeps His promises.