I've always read Isaiah 50-51 as a series of short proverbs that are unrelated to one another. But if we read them as a dialogue between God and Israel, with Isaiah cheering Israel on, we see a coherent message: Our Creator can empower us to overcome every obstacle we face.
He Hath Borne Our Griefs, and Carried Our Sorrows
Isaiah 50-55 appear frequently in the Book of Mormon. Lehi, Jacob, Abinadi, Alma, and Jesus all quote from these chapters. At the end of the book, Moroni again alludes to them, as if to remind the reader that they contain the heart of the Book of Mormon message.
It Meaneth Us
Nephi taught his brothers two things: how to place themselves inside the scriptural narrative and how to lengthen their perspective by identifying with their posterity. When he interpreted Isaiah 48 and 49 for them, he said, "It meaneth us in the days to come," indicating that their descendants would receive the promised blessings.
Hear Ye The Words of the Prophet
Nephi urged his brothers to listen carefully to the words of Isaiah. He emphasized that those words applied to them personally. Both of the chapters he quoted at that time, Isaiah 48 and 49, open with an invitation to listen. As we hear and follow the words of prophets, we experience peace.
They That Wait Upon the Lord
Isaiah promised that people who wait upon the Lord will be blessed with power and with vindication. Book of Mormon prophet Jacob added that the people of God wait for a specific event, the coming of the Messiah, and Alma showed that they wait with joyful expectation coupled with patience.
Prepare Ye the Way of the Lord
Isaiah described a messenger who would admonish Israel, "Prepare ye the way of the Lord." Like Matthew, Lehi identified this messenger as John the Baptist. Subsequent Book of Mormon prophets explained that we prepare the way of the Lord by repenting and walking in His paths, so that our reunion with Him will be joyful.
The Waters of Judah
Isaiah 48 is addressed to people who "are come forth out of the waters of Judah." The Book of Mormon adds the clarifying phrase "or out of the waters of baptism." That added phrase places the rest of the chapter, which condemns hypocrisy, within the context of a chosen covenant.
O Isles of the Sea
Nephi and Jacob took comfort from God's words to "the isles of the sea." They saw those scriptures as directed to them, reminding them that God was aware of them and also that they were not alone, that their people were all over the world.
Comfort Ye My People
Nephi quoted Isaiah 48 and 49 to "more fully persuade" his brothers "to believe in the Lord their Redeemer." Those chapters repeatedly refer to God as our Lord and our Redeemer, and similar references appear throughout Isaiah 40-49. We can rely on God to deliver us from everything that holds us captive.
Wonder Upon Wonder
Isaiah prophesied that God would do "a marvellous work and a wonder" among His people. The NIV stays closer to the Hebrew, rendering it: "wonder upon wonder." One thing that makes God's work wonderful is that He allows ordinary people to carry it out.