Second Nephi 25:7-8

But behold, I proceed with mine own prophecy, according to my plainness; in the which I know that no man can err; nevertheless, in the days that the prophecies of Isaiah shall be fulfilled men shall know of a surety, at the times when they shall come to pass. Wherefore, they are of worth unto the children of men, and he that supposeth that they are not, unto them will I speak particularly, and confine the words unto mine own people; for I know that they shall be of great worth unto them in the last days; for in that day shall they understand them; wherefore, for their good have I written them.

One can look for the fulfillment of many of Isaiah’s words in the events that are transpiring in our day and throughout this new dispensation of the gospel. Nephi knew that those who saw Isaiah’s prophecies come to pass could understand them (see, for example, Isaiah 29). If we do not read them, however, we cannot expect to understand them.

“The Book of Mormon is the world’s greatest commentary on the book of Isaiah” (McConkie, “Ten Keys to Understanding Isaiah,” p. 81). The Book of Mormon prophets loved the writings of Isaiah and quoted from them often. Large blocks of material are found in the Book of Mormon with inspired commentary and explanations. The Book of Mormon prophets obtained this material from the brass plates, which were written before 600  B.C. The Isaiah material in the Book of Mormon is, therefore, the oldest and most accurate available and provides commentary by prophets who, in some cases, had the same historical and cultural background as Isaiah had. The Lord Himself swore to the truthfulness of the Book of Mormon and, thus, to the truthfulness of Isaiah’s writings that are found therein (see D&C 17:6).