Recently I had a nephew ask me a question about the Isaiah chapters in the Book of Mormon. He was concerned that he wasn’t getting much out of the Isaiah chapters and wanted to know if I had any advice. I gave him some of the standard answers like getting a commentary to help and looking for the symbolism, but he didn't seem to be satisfied by my answer. The next day during my morning scripture study I re-read 2 Nephi Chapter 25 and had a bit of an epiphany. I came to the conclusion that the key to understanding the "Isaiah chapters" is contained in Chapter 25. Nephi explained why he included these chapters in the Book of Mormon. Carefully reading chapter 25 and outlining why Nephi said he included these chapters provides a study template as you re-read the previous chapters. Looking at these chapters through the Nephi's eyes will open our own eyes to what is contained in the books of Isaiah.
In order to fully understand what Nephi was trying to say, a person needs to read the entire chapter. However, verses 4 and 5 are particularly instructive.
4 Wherefore, hearken, O my people, which are of the house of Israel, and give ear unto my words; for because the words of Isaiah are not plain unto you, nevertheless they are plain unto all those that are filled with the spirit of prophecy. But I give unto you a prophecy, according to the spirit which is in me; wherefore I shall prophesy according to the plainness which hath been with me from the time that I came out from Jerusalem with my father; for behold, my soul delighteth in plainness unto my people, that they may learn.
5 Yea, and my soul delighteth in the words of Isaiah, for I came out from Jerusalem, and mine eyes hath beheld the things of the Jews, and I know that the Jews do understand the things of the prophets, and there is none other people that understand the things which were spoken unto the Jews like unto them, save it be that they are taught after the manner of the things of the Jews.
As you continue reading chapter 25 you will notice a continued emphasis on how the writings of Isaiah included in the Book of Mormon are targeted at the helping the Jews come to understand and know Jesus Christ. Recall what it says on the title page of the Book of Mormon:
"Which is to show unto the remnant of the house of Israel what great things the Lord hath done for their fathers; and that they may know the covenants of the Lord, that they are not cast off forever—And also to the convincing of the Jew and Gentile that Jesus is the Christ, the Eternal God, manifesting himself unto all nations”
Elder David A. Bednar said:
"The convincing and converting powers of the Book of Mormon come from both a central focus upon the Lord Jesus Christ and the inspired plainness and clarity of its teachings. Nephi declared, “My soul delighteth in plainness unto my people, that they may learn” (2 Nephi 25:4) The root word plain in this verse does not refer to things that are ordinary or simple; rather, it denotes instruction that is clear and easily understood."
"The Book of Mormon is the most correct of any book on earth because it centers upon the Truth (see John 14:6 and 1 Nephi 13:40) even Jesus Christ, and restores the plain and precious things that have been taken away from the true gospel (see 1 Nephi 13:26, 28–29, 32, 34–35, 40) The unique combination of these two factors—a focus on the Savior and the plainness of the teachings—powerfully invites the confirming witness of the third member of the Godhead, even the Holy Ghost. Consequently, the Book of Mormon speaks to the spirit and to the heart of the reader like no other volume of scripture. (David A. Bednar, “Watching with all perseverance” April 2010 LDS General Conference)
With those two thoughts in mind, now, President Nelson's prophetic direction given at the Worldwide Devotional for Youth becomes perfectly clear.
"My dear young brothers and sisters, these surely are the latter days, and the Lord is hastening His work to gather Israel. That gathering is the most important thing taking place on earth today. Nothing else compares in magnitude, nothing else compares in importance, nothing else compares in majesty. And if you choose to, if you want to, you can be a big part of it. You can be a big part of something big, something grand, something majestic!" (Russell M. Nelson, Worldwide Devotional for Youth, 3 June 2018)
The Book of Mormon is the tool the Lord has provided to help gather Israel in the last days. It was written for then entire world so they (including me) can come to know Jesus Christ.