Alma 51:16

In context (verses 14-16)

And it came to pass that when Moroni saw this, and also saw that the Lamanites were coming into the borders of the land, he was exceedingly wroth because of the stubbornness of those people whom he had labored with so much diligence to preserve; yea, he was exceedingly wroth; his soul was filled with anger against them.
And it came to pass that he sent a petition, with the voice of the people, unto the governor of the land, desiring that he should read it, and give him (Moroni) power to compel those dissenters to defend their country or to put them to death.
For it was his first care to put an end to such contentions and dissensions among the people; for behold, this had been hitherto a cause of all their destruction. And it came to pass that it was granted according to the voice of the people.

I usually don't get very much out of the war chapters in the Book of Mormon. I don't skip them when reading straight through, but I don't put in a lot of effort trying to apply them to my life. But these verses caught my eye when I was skimming through the book recently, and I thought they make a great example for the importance of being united. As we are told, "If ye are not one, ye are not mine." Or "A house divided against itself cannot stand."