(Isa. 51:1–7)
Isaiah 51 is a call to those who “follow after righteousness.” The call is repeated again and again: “hearken,” “look,” “hearken,” “lift up your eyes,” and again “hearken” (vv. 1–7). The call reminds the righteous that they are descendants of Abraham and Sarah and heirs to the blessings of the Abrahamic covenant. Their rock and quarry are Abraham and Sarah, from whom they descend. Even as Abraham and Sarah received promises when fulfillment seemed beyond hope, so will the Lord fulfill his promises to comfort Zion (v. 3).
Ultimately, of course, the rock from which the righteous come is God the Father, and Christ, who is called the Rock at least thirty-four times in the scriptures. For example, the Lord informed Enoch, “I am Messiah, the King of Zion, the Rock of Heaven, which is broad as eternity” (Moses 7:53).
(Donald W. Parry, Visualizing Isaiah [Provo, Utah: The Foundation for Ancient Research and Mormon Studies, 2001], 69.)