The allegory concludes with three verses covering two periods of time. The first (vv. 75–76) describes the millennium, wherein the Lord will lay up fruit for a long time. Nephi also described this time period apparently commenting upon Isaiah.
24 And the time cometh speedily that the righteous must be led up as calves of the stall, and the Holy One of Israel must reign in dominion, and might, and power, and great glory.
25 And he gathereth his children from the four quarters of the earth; and he numbereth his sheep, and they know him; and there shall be one fold and one shepherd; and he shall feed his sheep, and in him they shall find pasture.
26 And because of the righteousness of his people, Satan has no power; wherefore, he cannot be loosed for the space of many years; for he hath no power over the hearts of the people, for they dwell in righteousness, and the Holy One of Israel reigneth. [1 Nephi 22:24–26]
The millennium is when Christ will “dwell in righteousness with men on earth a thousand years” (D&C 29:11; see also Revelation 20:4).
The second period is the end of the millennium, when evil fruit will again appear and the Lord will again gather both the good and the bad together, preserving the good and casting away the bad.
22 And again, verily, verily, I say unto you that when the thousand years are ended, and men again begin to deny their God, then will I spare the earth but for a little season. [D&C 29:22]
Following this, the vineyard will be burned (Jacob 5:77). The temporal existence of the earth will then be completed and the program of the house of Israel finished. The earth will then be celestialized:
25 And again, verily I say unto you, the earth abideth the law of a celestial kingdom, for it filleth the measure of its creation, and transgresseth not the law—
26 Wherefore, it shall be sanctified; yea, notwithstanding it shall die, it shall be quickened again, and shall abide the power by which it is quickened, and the righteous shall inherit it. [D&C 88:25–26]