As I started to work out the battle game mechanic, I started thinking about how it all works. War is all throughout the scriptures. I thought that most of the verses that would use the mechanic would be Tales (white) or Trials (black), because most of the scriptures that talk about war are telling about battles, and going through war is certainly a trial.
I've long believed that even though at times, war may well be necessary, nobody really "wins". One side doesn't lose as many men or resources, and so they end up occupying the land, or getting their way, or whatever. So, really, the "winner" is the one that "loses the least".
So, in the battle mechanic, you pull a verse from one of your incomplete books, and one from one of your opponent's. Presumably, you'll pick a less important verse from yours and an important one from his. Thus, by picking the right cards, you "lose less".
Then, I started finding some scriptures where circumstances, like faith and divine intervention made a big difference in battle. So, those verses will protect books from being the targets of battle mechanics, or things like "The Title of Liberty", which allows you to search your deck for battle cards, much like Captain Moroni did when he waved the flag to recruit an army against the kingmen.
When we do a Book of Mormon set of cards, there's gonna be lots of battle-related cards. I mean, the whole books of Alma and Helaman are pretty much war, war, war... It'll be fun to see how this plays out in the game.