*Note: During the thousand-year history of Lehi and his descendants, there are six accounts of a Lehi type exodus. These accounts illustrate how the Lord tells His servants to take His people and "depart into the wilderness." In each exodus account, the righteous people leave their prideful brethren, who have sinned against light and knowledge and have brought themselves under condemnation. These examples are a type for a latter-day exodus, as prophesied by Isaiah. (2 Nephi 8:10-11, 16:12, 20:20-21, 21:15-16). The other five exodus accounts are found in 2 Nephi 5:5, Omni 1:13, Mosiah 18:34, 22:11, and Alma 27:11-4. A seventh took place in 2,200 BC (Ether 1:39-42).

Paraphrase of Words of Mormon, verses 3-7……3:

After I had engraved the Nephite history down to King Benjamin by referring to Nephi's large plates, I found Nephi's small plates. They contain many of Nephi's words and a brief account of the prophets from Jacob down to King Benjamin. What pleases me most about Nephi's small plates is their account of the prophecies of Christ's coming. My ancestors knew that many of these prophecies had been fulfilled in their day.
I know the prophecies of my day have been fulfilled, and that the prophecies not yet fulfilled (like those made by Isaiah) surely will be. Because these prophecies will be fulfilled, I will pattern the rest of my record after them. I will do this as I continue referring to Nephi's large plates.

Note: Among all the plates available to Mormon, the few writings ("less than 1%") that he included in "the rest of his record" contain events that strictly followed the pattern set forth by Isaiah’s prophecies. Isaiah wrote about patterns that will repeat themselves in the last days. This is why Mormon's record (The Book of Mormon), a book written to warn latter-day Israel, is patterned after Isaiah’s writings.

I know the record of these small plates will also be choice to my brethren, the Lamanites, in the last days. I am putting the small plates with mine because the Lord's Spirit tells me to. I do not know exactly why, for I know not the future, but it must be for a wise purpose known to the Lord, who works His will through me.

Note: This “wise purpose” was the Lord knowing that “The Book of Lehi”, which Nephi had included in his record…

Paraphrase of 1 Nephi 1:17……I will make a record of my life, but first I will write part of my father's history (Book of Lehi) on metal plates that I have made.

…would be lost. The Book of Lehi was part of 116 pages of lost manuscripts. Nephi was told to make a second, more brief record of the journeys, and particularly of the prophecies of Christ, on small plates. Mormon found and inserted these plates directly (thus no commentary), which became The First Book of Nephi through The Book of Omni.