Jesus taught: “And now, behold, I say unto you, that ye ought to search these things. Yea, a commandment I give unto you that ye search these things diligently; for great are the words of Isaiah. For surely he spake as touching all things concerning my people which are of the house of Israel; therefore it must needs be that he must speak also to the Gentiles. And all things that he spake have been and shall be, even according to the words which he spake.” (3 Nephi 23:1-3).
My brother has a website that shows side-by-side comparisons of all the extensive Isaiah quotes in the Book of Mormon. Differences are shown in color. This is an interesting project and is helpful for those who are want to learn what the Book of Mormon adds to our understanding of Isaiah’s teachings. Many of the changes are minor but some are significantly clarifying.