I suddenly feel a great interest in figuring out the logic of these verses.
Nephi is grieved because of the hardness of his brothers’ hearts and prays for them. Is he worried for their sakes, for their salvation, or is he worried that their family won’t really be able to do whatever it is God wants them to do because Laman and Lemuel will be holding their family back? Is he worried about his brothers as individuals or as members of their group?
The answer to the problem (whichever it is) comes in two parts:
1) Inasmuch as they rebel against Nephi, they will be cut off from the presence of the Lord
2) In the day that they rebel against God, they will be cursed and have no power over Nephi’s seed
The logic attached to the first part is really kind of cool: inasmuch as they rebel against Nephi (who is being blessed, prospered, and led, according to v.19-20), they will be cut off from the Lord (that is, they will not be blessed, prospered, and led.) But, if this happens, God will make Nephi a ruler and a teacher over them. At first this sounds like a position of power granted as some prize for being more righteous that someone else. But I think the move is pretty clearly an answer to help Laman and Lemuel: if they are cut off from God’s presence, then Nephi is given the authority to be a teacher (that is, to be in God’s presence for them, to receive instruction for them, and so forth). In the grander scheme of history, the Nephites’ record becomes this teacher for the Lamanites’s descendants.
It’s all a bit complicated though. If they rebel against Nephi, then Nephi has authority to rule over them. You would think it would have to go the other way around, that he would have to have authority first for them to even rebel against Nephi. In fact, the other parts seem backwards too: they are cut off from the presence of the Lord and then rebel against God. Wouldn’t it make more sense the other way around? It would instead go like this: If they rebel against God, then they are cut off from his presence. If that happens, Nephi is set up as a teacher and a ruler. If they rebel against Nephi, then they are cursed and have no power over him. That would be logic I would set up myself! So why is the logic otherwise? I don’t have any great ideas, myself! Anyone out there (who might actually find and read this) have any thoughts?