One more indulgence in post Seminary class ponderings...
In Alma 23, we learn that when a group of Lamanites, who decide to call themselves the Anti-Nephi-Lehies, are converted they "never did fall away."
In class, we tried to analyze why the Anti-Nephi-Lehies never fell away and why others do fall away (after true conversion).
There probably isn't a simple answer (wouldn't that make it easy) but there are plenty of hints. The Anti-Nephi-Lehies are called "firm" and once they accept the gospel they became "a very industrious people" (hmm...too busy to get into trouble?)
But another impressive thing the Anti-Nephi-Lehies did was their decision to bury their swords deep in the earth. Alma 24: 17-18 reads: "..and they did bury them up deep in the earth. And this they did, it being in their view a testimony to God, and also to men, that they would never use weapons again for the shedding of man's blood..."
Burying their swords was a symbolic gesture but their pact and commitment stuck. And while there is no single answer for why they never fell away spiritually I think this covenant along with their consistency (in firmness and in their industrious nature) were pretty big factors!
So, just for good measure, I brought plastic swords to Seminary so we could bury them outside; thinking about some trait we might want to bury deep in the earth! Good luck to future archaeologists trying to make sense of this "find" in the church parking lot!