Isaiah’s words continue by telling people to "Look unto the rock from whence ye are hewn." This is how the victory of the Lord will be won. First, his people must look. But what rock are we hewn from to which we must look? Consider the eternal bond of Abraham and Sarah (the promise), the priesthood that Peter would be entrusted with when he was called the Rock (the power), the eternal nature of the covenants made in the temple also called the dome of the rock (the place); in other words, the rock of our Redeemer.
As Jacob continues to read, his people heard a number of words and phrases that would have helped them remain firmly founded on the rock of the Lord. They were assured that the Lord will comfort them in all their "waste places" (8:3). His law, judgment, righteousness, and salvation shall extend to judge the people. Those on "the isles of the sea shall wait upon" the Lord (8:5), if the law of God is written in their heart (8:7).
Three times, the Lord calls for his people to "Awake, Awake" (8:9, 17, 24), as the redeemed of the Lord shall return, and the Lord will plead the cause of his people, as the Lord will take the cup of trembling out of the hands of His people (8:22). The scene of God’s judgment will reappear in Jacob’s text in chapter 9, where the word judgment appears seven times.
In one other way, the words of Isaiah pave the way for Jacob’s main words to his people. Seven times Isaiah used the emphatic opening expression, "O …" in Isaiah 51 (2 Nephi 8): O my nation, O arm of the Lord, O Jerusalem, O Zion, O Jerusalem, O Jerusalem, O captive. Jacob will continue this pattern, beginning fourteen of his powerful exclamations this same way: O the wisdom, O how great the goodness, O how great the plan, O the greatness and justice, O the greatness of the mercy, O how great the holiness, O that cunning plan, O the vainness, O my beloved brethren (five times), and O Lord God Almighty. Not just stylistically, but thematically, Jacob’s words elaborate and personalize many of the main themes found in the words of Isaiah that Nephi assigned Jacob to read and teach.
Book of Mormon Central, "Why Did Helaman Compare Christ to a Rock? (Helaman 5:12)," KnoWhy 176 (August 30, 2016).