Verse 8 is Jacob's transition from the example of the Jews of the Old World to his people in the New World. The key to this change is "from the isles of the sea," which Nephi and now Jacob specifically interpret as referring to themselves. Thus Jacob returns to the redemption theme of Isaiah. Remember that Nephi specifically has the phrase "isles of the sea" in his redaction of Isaiah 49:
1 Ne. 21:8 Thus saith the Lord: In an acceptable time have I heard thee, O isles of the sea, and in a day of salvation have I helped thee; and I will preserve thee, and give thee my servant for a covenant of the people, to establish the earth, to cause to inherit the desolate heritages;
Compare to Isaiah in the KJV:
Isa. 49:8 Thus saith the LORD, In an acceptable time have I heard thee, and in a day of salvation have I helped thee: and I will preserve thee, and give thee for a covenant of the people, to establish the earth, to cause to inherit the desolate heritages;
Whether or not the "isles of the sea" is part of the brass plates, or an insertion/interpretation by Nephi, it is absolutely certain that Nephi and Jacob saw the phrase "isles of the sea" to be a prophetic discussion of their people. It is in that tradition that Jacob uses that phrasing to begin the shift in emphasis.