Here the knife is thrust! While the ignorant and even "incapable" children will be saved with the righteous, the priests of Noah ought to fear and tremble! Abinadi describes a set of people who are not among the righteous who are saved in the first resurrection. These are people who "rebel against him and die in their sins." These are the priests of Noah. Abinadi knows that the priests have an understanding of the mission of the atoning Messiah. We have seen at several points in the discourse where Abinadi presumes their understanding. This is not new information to them, but a point against which they have "willfully rebelled."
Abinadi began his discourse by noting: " Mosiah 12:37 …Have ye done all this? I say unto you, Nay, ye have not. And have ye taught this people that they should do all these things? I say unto you, Nay, ye have not."
Now he declares that the unrighteous are they: "that have known the commandments of God, and would not keep them." This is very pointed directed at the very priests who are attempting to accuse Abinadi of the very same thing.