Isaiah 49:24 is not quoted above because it is identical to First Nephi except the bold For at the beginning. “For” ties the question to the previous verse more firmly, where it is prophesied that the Gentiles would bow down to the house of Israel. Thus the “prey” is the House of Israel, which has been captive to the “mighty” (Gentiles). The question suggests that it may seem highly unlikely that Israel could overcome the mighty gentile nations who have been ruling the world for hundreds of years. However, the Lord, who is “mightier than all the earth” (1 Nephi 4:10), will be on Israel’s side, as the Prophet Joseph made clear.
25 But thus saith the Lord; even the captives of the mighty shall be taken away, and the prey of the terrible shall be delivered; for the mighty God shall deliver his covenant people. For thus saith the Lord, I will contend with them that contend with thee, and I will save thy children. [JST, Isaiah 49:25).
The King James text is identical to the First Nephi text (v. 25) except the Nephi text says him, and the KJV says “them.” However the Prophet Joseph did not change the JST to “them,” one being singular and the other plural. Both pronouns fit, and does not affect the meaning; the Nephite text referring to the Gentiles as a singular unit, and the KJV and the JST referring to the nations as plural. The JST change is the way it was quoted by Jacob in 2 Nephi 6:17, except Jacob does not quote the last phrase “and I will save thy children.” This suggests that Jacob was paraphrasing to assure his people that the “I” was referring to the mighty God who would deliver his covenant people. Again the message is not changed. God will fulfill the covenant he made to Israel through the Gentiles.
The only difference in the King James text (v. 26) is an “and” at the beginning of the second phrase, therefore it is not quoted above. Nephi interprets these verses for us:
13 And the blood of that great and abominable church, which is the whore of all the earth, shall turn upon their own heads; for they shall war among themselves, and the sword of their own hands shall fall upon their own heads, and they shall be drunken with their own blood.
14 And every nation which shall war against thee, O house of Israel, shall be turned one against another, and they shall fall into the pit which they digged to ensnare the people of the Lord. And all that fight against Zion shall be destroyed, and that great whore, who hath perverted the right ways of the Lord, yea, that great and abominable church, shall tumble to the dust and great shall be the fall of it. [1 Nephi 22:13–14]
These waring factions within the great and abominable church will be part of Israel’s deliverance. It will be as Jesus taught: Every kingdom divided against itself is brought to desolation; and every city or house divided against itself shall not stand (Matthew 12:25).
A second reason is that “the Lord, will fight [Israel’s] battles” as promised (D&C 98:37). The Lord will establish Zion and protect her. The righteous will be protected, and those who pervert the ways of the Lord will fall.