18 And it came to pass that because of so much contention and so much difficulty in the government, that they had not kept sufficient guards in the land of Zarahemla; for they had supposed that the Lamanites durst not come into the heart of their lands to attack that great city Zarahemla.
The Nephites time and again illustrate the danger of being politically and socially divided to the point where external threats can metastasize. They also illustrate the danger of becoming too complacent or comfortable with our strengths. When we think we are strong, then we are likely to be divided by strife. And we are likely to neglect our strengths and not build an adequate reservoir of strength.
But the failed Lamanite attack backfires spectacularly– though with great losses among the Nephites. The Lamanites overreached dramatically. Their attacks unified the people again. And they fought back with renewed strength. So to does Satan tend to overreact and overreach. His tactics will ultimately spark resistance both among believers and internally within indiviudals.