[for it shall come to pass in that day, saith the Father, that I will cut off thy horses out of the midst of thee, and I will destroy thy chariots;]: In the days of the Triumphant Messiah the tables will be turned on the powerful of the world. Those who were once the most powerful and overran Israel will be overrun by Israel as led by the Triumphant Messiah. The horses and chariots are symbols of military might in the Old World. The “cutting off” of those means of warfare is an indication of their defeat. They will be defeated in such a way that they no longer have the ability to wage war.
In spite of references in the Book of Mormon to horses and chariots (for instance, Alma 18:9-11), there is no indication of their use in battle. The Micah passage is clearly battle-oriented. How this passage would have been understood by the Nephites in their Mesoamerican context is not known.
[ I will cut off the cities of thy land, and throw down all thy strongholds]: Those who used to have powerful dependent cities will lose them. Those who had strong fortified cities will have them destroyed. This is a furtherance of the imagery of complete defeat.
[ I will cut off witchcrafts out of thy land, and thou shalt have no more soothsayers]: God will destroy competing religions. The witchcrafts and soothsayers were not those with the connotations we typically give those words in modern societies, but were rather the prophets of the false gods.
[Thy graven images I will also cut off, and thy standing images out of the midst of thee, and thou shalt no more worship the works of thy hands]: Just as the prophets of the false gods will be removed, so too will the idols of those gods. The images that the powerful of the world worship in Micah’s day will be destroyed and replaced by the true God.
[ I will pluck up thy groves out of the midst of thee; so will I destroy thy cities]: The groves were locations of religious worship. So thoroughly are the cities to be destroyed that even the outlying groves for worship will be destroyed.
[it shall come to pass that all lyings, and deceivings, and envyings, and strifes, and priestcrafts, and whoredoms, shall be done away.] This is a passage added to the Micah text. In addition to the militaristic destructions, all wickedness will be removed.
[it shall come to pass, saith the Father, that at that day whosoever will not repent and come unto my Beloved Son, them will I cut off from among my people, O house of Israel]: This is also an addition to the Micah text. This picks up on the theme of adoption. Those who are righteous and believe mayh be adopted. Those who refuse the gospel will be cut off from the covenant of the House of Israel.
[ I will execute vengeance and fury upon them, even as upon the heathen, such as they have not heard.] : The Triumphant Messiah will finally destroy wickedness, with “vengeance and fury.” The phrase “even as upon the heathen” is not to be read that the destruction will be upon the gentiles “even as upon the heathen,” but rather than the heathen as synonymous with the Gentiles will be the recipients of this action. The New International Version translates this phrase:
Micah 5:15
15 I will take vengeance in anger and wrath upon the nations that have not obeyed me.
Reference: this is a long insertion from Micah:
Micah 5:10-15
10 [Yea, wo be unto the Gentiles except they repent; for] (And) it shall come to pass in that day, saith the LORD, that I will cut off thy horses out of the midst of thee, and I will destroy thy chariots:
11 And I will cut off the cities of thy land, and throw down all thy strong holds:
12 And I will cut off witchcrafts out of thine hand; and thou shalt have no more soothsayers:
13 Thy graven images also will I cut off, and thy standing images out of the midst of thee; and thou shalt no more worship the work of thine hands.
14 And I will pluck up thy groves out of the midst of thee: so will I destroy thy cities.
15 And I will execute vengeance in anger and fury upon the heathen, such as they have not heard.
3 Nephi 21:20
[19 And it shall come to pass that all lyings, and deceivings, and envyings, and strifes, and priestcrafts, and whoredoms, shall be done away.
20 For it shall come to pass, saith the Father, that at that day whosoever will not repent and come unto my Beloved Son, them will I cut off from among my people, O house of Israel;]
The additional text at the beginning of verse 14 (Micah 5:10) serves to tie this insertion with the rest of the discourse. The only other change is interesting in that it is in the inclusion of what are now two verses between Micah 5:14 and 15. These verses further the theme of the destruction of the wicked in the last days, and in particular, 3 Nephi 21:20 reiterates the penalty of exclusion from the covenant of the House of Israel, which has been a strong theme of this discourse.
Textual: This is the end of a chapter in the 1830 edition. This is an interesting division in chapters because the discourse clearly continues, which is the reason that Orson Pratt tied the next verse into this chapter rather than separating it. The original chapter break may have been created by Mormon who typically breaks chapters at the end of extended textual insertions. Perhaps this inserted text from Micah qualified.