Much of this chapter is a warning for the Nephites, and compares the Lamanites and the Nephites and their prophetic future. It’s typical for those who have not read the Book of Mormon in depth to think that the Book of Mormon is a straightforward account of “good guys” and “bad guys” (such as described by Thomas O’Dea, for instance). I’d wager that most of those who’ve read the book through realise this is not the case, and this chapter is likewise a good instance of that. At first, even while warning the Nephites, it seems to be making that distinction (vv. 3-4):
Yea, wo unto this people who are called the people of Nephi except they shall repent, when they shall see all these signs and wonders which shall be showed unto them; for behold, they have been a chosen people of the Lord; yea, the people of Nephi hath he loved, and also hath he chastened them; yea, in the days of their iniquities hath he chastened them because he loveth them.
But behold my brethren, the Lamanites hath he hated because their deeds have been evil continually, and this because of the iniquity of the tradition of their fathers…
Yet there then comes a significant twist (vv. 4-5, 7):
… But behold, salvation hath come unto them through the preaching of the Nephites; and for this intent hath the Lord prolonged their days.
And I would that ye should behold that the more part of them are in the path of their duty, and they do walk circumspectly before God, and they do observe to keep his commandments and his statutes and his judgments according to the law of Moses.
And behold, ye do know of yourselves, for ye have witnessed it, that as many of them as are brought to the knowledge of the truth, and to know of the wicked and abominable traditions of their fathers, and are led to believe the holy scriptures, yea, the prophecies of the holy prophets, which are written, which leadeth them to faith on the Lord, and unto repentance, which faith and repentance bringeth a change of heart unto them—
Many of the Lamanites have converted, and not only converted, but have genuinely remained faithful. And because of this, they will be blessed (vv. 10-12):
And now, because of their steadfastness when they do believe in that thing which they do believe, for because of their firmness when they are once enlightened, behold, the Lord shall bless them and prolong their days, notwithstanding their iniquity—
Yea, even if they should dwindle in unbelief the Lord shall prolong their days, until the time shall come which hath been spoken of by our fathers, and also by the prophet Zenos, and many other prophets, concerning the restoration of our brethren, the Lamanites, again to the knowledge of the truth—
Yea, I say unto you, that in the latter times the promises of the Lord have been extended to our brethren, the Lamanites; and notwithstanding the many afflictions which they shall have, and notwithstanding they shall be driven to and fro upon the face of the earth, and be hunted, and shall be smitten and scattered abroad, having no place for refuge, the Lord shall be merciful unto them.
Despite future “dwindl[ing] in unbelief”, and despite the afflictions they will suffer, the Lamanites will ultimately be blessed. Again, it’s been commonplace for scholars to fit the Book of Mormon into the context of common 19th century American beliefs about the USA being the new Israel. But (as I discuss in the 3rd and 5th chapters of The Book of Mormon and its relationship with the Bible), the Book of Mormon does not articulate those beliefs: rather it is the descendants of Israel (including the descendants of the Lamanites) who are heirs of the promises attached to Israel, not the Gentile colonists, despite whatever role said colonists may have in being a conduit for the Gospel (much as the Nephites have been here in fact).
So what of the Nephites?
Therefore I say unto you, it shall be better for them than for you except ye repent.
For behold, had the mighty works been shown unto them which have been shown unto you, yea, unto them who have dwindled in unbelief because of the traditions of their fathers, ye can see of yourselves that they never would again have dwindled in unbelief.
Therefore, saith the Lord: I will not utterly destroy them, but I will cause that in the day of my wisdom they shall return again unto me, saith the Lord.
And now behold, saith the Lord, concerning the people of the Nephites: If they will not repent, and observe to do my will, I will utterly destroy them, saith the Lord, because of their unbelief notwithstanding the many mighty works which I have done among them; and as surely as the Lord liveth shall these things be, saith the Lord.
A fascinating thought struck me while reading this: it seems to suggest that the (future? the “again” seems suggestive) Lamanite “dwindl[ing] in unbelief” could have been outright prevented, had the Lord showed them the same miracles that he did the Nephites. So why didn’t he? Would acting in this way somehow invalidate the purpose of mortal existence (by robbing them of the need to act in faith)? Whatever the answer, however, one thing is very clear, which is that while the Nephites have been favoured, this now turns to their condemnation. The Lamanites would not have gone astray had they been witnessed the same miracles, and when aware of the truth are faithful. The Nephites however have still apostatized. Thus while the Lamanites will be preserved and ultimately blessed, the Nephites face the threat of being “utterly destroy[ed]”.