Just like Nephi, Jacob applies Isaiah’s words directly to his people’s needs. They saw the Nephites as the object of Isaiah’s prophetic utterings—as living in the times of the fulfillment for many of them.
History: Whatever the Nephites’ political and social makeup—which I have already argued included a strong injection from the local population—it is clear that Jacob considers all of them to be heirs to the blessings of Israel. Consequently, the native peoples who have become Nephi’s subjects politically have also been adopted into the house of Israel. Because of that adoption, the prophecies Jacob will expound apply to them as well.