In 3 Nephi 27:32 we find the Savior prophesying concerning the future generations of the Nephites:
But behold, it sorroweth me because of the fourth generation from this generation, for they are led away captive by him even as was the son of perdition; for they will sell me for silver and for gold, and for that which moth doth corrupt and which thieves can break through and steal. And in that day will I visit them, even in turning their works upon their own heads.
This 4-generation prophecy builds on the vision of Nephi wherein he saw the following:
11: And the angel said unto me: Look! And I looked, and beheld three generations pass away in righteousness; and their garments were white even like unto the Lamb of God.
12: And the angel said unto me: These are made white in the blood of the Lamb, because of their faith in him. And I, Nephi, also saw many of the fourth generation who passed away in righteousness.
15: And it came to pass that I looked and beheld the people of my seed gathered together in multitudes against the seed of my brethren; and they were gathered together to battle.
20: And it came to pass that I beheld, and saw the people of the seed of my brethren that they had overcome my seed; (1 Nephi 12:11-12, 15, 20)
Nephi also repeats this 4-generation prophecy in 2 Nephi 26:9-11:
But the Son of righteousness shall appear unto them; and he shall heal them, and they shall have peace with him, until three generations shall have passed away, and many of the fourth generation shall have passed away in righteousness.
And when these things have passed away a speedy destruction cometh unto my people; for, notwithstanding the pains of my soul, I have seen it; wherefore, I know that it shall come to pass; and they sell themselves for naught; for, for the reward of their pride and their foolishness they shall reap destruction; for because they yield unto the devil and choose works of darkness rather than light, therefore they must go down to hell.
For the Spirit of the Lord will not always strive with man. And when the Spirit ceaseth to strive with man then cometh speedy destruction, and this grieveth my soul
Almost 500 years later [abt. 73 B.C.], Alma2 came to his son Helaman and repeated this prophecy concerning the destruction of the Nephites. Helaman recorded this prophecy as follows :
9: But behold, I have somewhat to prophesy unto thee; but what I prophesy unto thee ye shall not make known; yea, what I prophesy unto thee shall not be made known, even until the prophecy is fulfilled; therefore write the words which I shall say.
10: And these are the words: Behold, I perceive that this very people, the Nephites, according to the spirit of revelation which is in me, in four hundred years from the time that Jesus Christ shall manifest himself unto them, shall dwindle in unbelief.
11: Yea, and then shall they see wars and pestilences, yea, famines and bloodshed, even until the people of Nephi shall become extinct--
12: Yea, and this because they shall dwindle in unbelief and fall into the works of darkness, and lasciviousness, and all manner of iniquities; yea, I say unto you, that because they shall sin against so great light and knowledge, yea, I say unto you, that from that day, even the fourth generation shall not all pass away before this great iniquity shall come.
13: And when that great day cometh, behold, the time very soon cometh that those who are now, or the seed of those who are now numbered among the people of Nephi, shall no more be numbered among the people of Nephi.
14: But whosoever remaineth, and is not destroyed in that great and dreadful day, shall be numbered among the Lamanites, and shall become like unto them, all, save it be a few who shall be called the disciples of the Lord; and them shall the Lamanites pursue even until they shall become extinct. And now, because of iniquity, this prophecy shall be fulfilled. (Alma 45:9-14)
Just previous to the Savior's birth (about 6 B.C.), Samuel the Lamanite included words concerning the Nephite destruction among his prophecies:
5: And he said unto them: Behold, I, Samuel, a Lamanite, do speak the words of the Lord which he doth put into my heart; and behold he hath put it into my heart to say unto this people that the sword of justice hangeth over this people; and four hundred years pass not away save the sword of justice falleth upon this people.
6: Yea, heavy destruction awaiteth this people, and it surely cometh unto this people, and nothing can save this people save it be repentance and faith on the Lord Jesus Christ, who surely shall come into the world, and shall suffer many things and shall be slain for his people.
7: And behold, an angel of the Lord hath declared it unto me, and he did bring glad tidings to my soul. And behold, I was sent unto you to declare it unto you also, that ye might have glad tidings; but behold ye would not receive me.
8: Therefore, thus saith the Lord: Because of the hardness of the hearts of the people of the Nephites, except they repent I will take away my word from them, and I will withdraw my Spirit from them, and I will suffer them no longer, and I will turn the hearts of their brethren against them.
9: And four hundred years [A.D. 394?] shall not pass away before I will cause that they shall be smitten; yea, I will visit them with the sword and with famine and with pestilence.
10: Yea, I will visit them in my fierce anger, and there shall be those of the fourth generation who shall live, of your enemies, to behold your utter destruction; and this shall surely come except ye repent, saith the Lord; and those of the fourth generation shall visit your destruction.
[Note* This is probably referring to the final battles]
11: But if ye will repent and return unto the Lord your God I will turn away mine anger, saith the Lord; yea, thus saith the Lord, blessed are they who will repent and turn unto me, but wo unto him that repenteth not.
12: Yea, wo unto this great city of Zarahemla; for behold, it is because of those who are righteous that it is saved; yea, wo unto this great city, for I perceive, saith the Lord, that there are many, yea, even the more part of this great city, that will harden their hearts against me, saith the Lord.
13: But blessed are they who will repent, for them will I spare. But behold, if it were not for the righteous who are in this great city, behold, I would cause that fire should come down out of heaven and destroy it.
14: But behold, it is for the righteous' sake that it is spared. But behold, the time cometh, saith the Lord, that when ye shall cast out the righteous from among you, then shall ye be ripe for destruction; yea, wo be unto this great city, because of the wickedness and abominations which are in her.
15: Yea, and wo be unto the city of Gideon, for the wickedness and abominations which are in her.
16: Yea, and wo be unto all the cities which are in the land round about, which are possessed by the Nephites, because of the wickedness and abominations which are in them.
17: And behold, a curse shall come upon the land, saith the Lord of Hosts, because of the people's sake who are upon the land, yea, because of their wickedness and their abominations.
18: And it shall come to pass, saith the Lord of Hosts, yea, our great and true God, that whoso shall hide up treasures in the earth shall find them again no more, because of the great curse of the land, save he be a righteous man and shall hide it up unto the Lord.
19: For I will, saith the Lord, that they shall hide up their treasures unto me; and cursed be they who hide not up their treasures unto me; for none hideth up their treasures unto me save it be the righteous; and he that hideth not up his treasures unto me, cursed is he, and also the treasure, and none shall redeem it because of the curse of the land. (Helaman 13:5-19)
That Mormon was able to include prophecies such as these in his record signifies their importance. That he was able to cite their fulfillment is a testament to his record. The following verses are a direct fulfillment of the vision of Nephi and the timetable prophesied by the Savior concerning the fourth generation:
(1st generation) In 4 Nephi 1:18 we find that "an hundred and ten years had passed away; and the first generation from Christ had passed away, and there was no contention in all the land."
(2nd generation) In 4 Nephi 1:22 we find that "two hundred years had passed away; and the second generation had all passed away save it were a few."
(3rd generation) In 4 Nephi 1:48 we find that "when three hundred and twenty years had passed away, Ammaron, being constrained by the Holy Ghost, did hide up the records which were sacred--yea, even all the sacred records which had been handed down from generation to generation, which were sacred--even until the three hundred and twentieth year from the coming of Christ."
a. In Mormon 1:2 we find that "about the time that Ammaron hid up the records unto the Lord, he came unto me [Mormon], . . . and Ammaron said unto me . . . when ye are about twenty and four years old I would that ye should . . . take the plates of Nephi unto yourself . . . and ye shall engrave on the plates of Nephi all the things that ye have observed concerning this people.
b. In about the year A.D. 322, "there began to be a war between the Nephites . . . and the Lamanites" (Mormon 1:8)
c. Mormon writes: "In the three hundred and sixty and second year . . . I Mormon did utterly refuse from this time forth to be a commander and a leader of this people, because of their wickedness and abomination . . . and I did even as the Lord had commanded me; and I did stand as an idle witness to manifest unto the world the things which I saw and heard according to the manifestations of the Spirit which had testified of things to come." (Mormon 3:8, 11, 16)
d. Mormon writes, "when three hundred and eighty and four years had passed away, we had gathered in all the remainder of our people unto the land of Cumorah. . . . And it came to pass that they [the Lamanites] came to battle against us. . . . [and] they [went] through and hew[ed] down all my people save it were twenty and four of us." (Mormon 6:5, 8, 11, 15)
e. Moroni writes, "Behold four hundred years have passed away since the coming of our Lord and Savior [A.D. 400?]. And behold, the Lamanites have hunted my people, the Nephites, down from city to city and from place to place, even until they are no more." (Mormon 8:6)
As for the rest of the Savior's prophecy, he builds on words which he had taught previously:
Lay not up for yourselves treasures upon earth, where moth and rust doth corrupt, and thieves break through and steal; but lay up for yourselves treasures in heaven, where neither moth nor trust doth corrupt, and where thieves do not break through nor steal. For where your treasure is, there will your heart be also. (3 Nephi 13:19-21)
It is interesting to note that Samuel the Lamanite also prophesied of slippery treasures relative to the Nephite destruction (see Helalman 13:17-19). To his credit, Mormon noted the fulfillment of that prophecy (see Mormon 1;19). Moroni also noted the association of slippery treasures (degenerate thievery) among the Jaredites at the time of their destruction (see Ether 14:1-2). [Alan C. Miner, Personal Notes] [See the commentary on Mormon 1:19; Ether 14:1-2]