Verses 10-13 set the stage for the analysis. Jacob ties Isaiah to the New World struggle. Thus in Jacob's reading of Isaiah, Isaiah's passages appear to relate to both the New World, and apparently a current situation. While Jacob does not at this point specifically tell his audience that these verses are directed at them, he likely does not need to, as they understand their current situation much better than we do at this distant time. However, it is useful for a modern audience to remember in this particular context that Jacob is very specifically relating Isaiah to a current people and circumstance. In his introduction, Jacob states:
2 Ne. 6:5 And now, the words which I shall read are they which Isaiah spake concerning all the house of Israel; wherefore, they may be likened unto you, for ye are of the house of Israel. And there are many things which have been spoken by Isaiah which may be likened unto you, because ye are of the house of Israel.
Thus all of what Jacob is doing is pointing to a particular circumstance that faces his community.
As he develops his theme of relevancy to their current situation, Jacob is citing a revelation from God, but which one? Jacob does not tell us, but the reference is Nephi. The clue is the context of those who fight against Zion. In this reference, those who fight against Zion are linked to the verses about the liberty of the land of promise, thus the context for this promise is the New World. The language returns to Nephi:
1 Ne. 22:14 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.
Note the two components of the fight against Zion in Nephi's vision. The first is the battle itself, and the second is the opponent, the "great and abominable church." With those two aspects in mind, examine Jacob's text from the first day of this sermon:
2 Ne. 6:12 And blessed are the Gentiles, they of whom the prophet has written; for behold, if it so be that they shall repent and fight not against Zion, and do not unite themselves to that great and abominable church, they shall be saved; for the Lord God will fulfil his covenants which he has made unto his children; and for this cause the prophet has written these things.
Jacob explicitly notes the fight against Zion in the context of the great and abominable church. His reference is therefore clearly Nephi's vision. In Jacob, however, the great and abominable church is still the enemy, and in contrast to the typical outsider role of the gentiles, they become the agents of the salvation of Zion (which is the theme of the Isaiah text upon which the sermon is built).