It is impossible for Aaron to explain what it might mean to be cast off if the king does not believe in Yahweh. As when Ammon taught Lamoni, Aaron understands that the Lamanite concept of God differed from that of the Nephites. This picture becomes a little clearer when Lamoni’s father comments that “the Amalekites say that there is a God” and mentions that he allows them to worship as they like. This statement confirms what we already know of the Nehorites: They believe some of the Nephite gospel but have introduced other, heretical beliefs.
Lamoni’s father has no real experience with Yahweh; but when Aaron tells him there is such a God, he says that he is willing to believe. Almost certainly, Lamoni’s father is a polytheist and was quite familiar with the concept of regional and multiple gods. It was not hard to simply add another god to the pantheon.
Culture: The difference between Lamanite and Amalekite beliefs is not spelled out, but the fact that Lamoni’s father “granted unto them” to continue their beliefs confirms that Lamanite and Amalekite beliefs are different. Thus, the Book of Mormon confirms the existence of at least three religions: (1) the Nephite religion, which naturally receives the most attention, (2) the order of the Nehors, which is an apostate form of the Nephite religion, and (3) the Lamanite religion, which is the least discussed but is different from both the Nehorite and Nephite beliefs in that it acknowledges a different god or gods. There is no reason to suppose that the Lamanite religion was other than a variation of the general Mesoamerican religion.