Words of Mormon 1

The Words of Mormon are basically editorial notes as to why Mormon added the small plates to his abridgment of their history. Elder Jeffrey R. Holland said that the small plates provides more information than was lost on the 116 pages:

“At least six times in the Book of Mormon the phrase ‘for a wise purpose’ is used in reference to the making, writing, and preserving of the small plates of Nephi (see 1 Nephi 9:5; Words of Mormon 1:7; Alma 37:2, 12, 14, 18). You and I know the wise purpose—the most obvious one—was to compensate for the loss of the earlier mentioned 116 pages of manuscript. 

“But it strikes me that there is a wiser purpose than that. . . . The key to such a suggestion of a wiser purpose is in verse 45 of Doctrine and Covenants section 10. As the Lord instructs Joseph . . . he says, ‘Behold, there are many things engraven upon the [small] plates of Nephi which do throw greater views upon my gospel’ (emphasis added). 

“So, clearly, this was not . . . tit for tat, this for that— you give me 116 pages of manuscript and I’ll give you 142 pages of printed text. Not so. We got back more than we lost. And it was known from the beginning that it would be so. It was for a wiser purpose. We do not know exactly what we missed in the 116 pages, but we do know that what we received on the small plates was the personal declarations of three great witnesses [Nephi, Jacob, and Isaiah], three of the great doctrinal voices of the Book of Mormon, testifying that Jesus is the Christ. . . . 

“In fact, I think you could make a pretty obvious case that the sole purpose of the small plates was to give a platform for these three witnesses” (“A Standard unto My People” [Church Educational System symposium on the Book of Mormon, Aug. 9, 1994], 9–10; see LDS.org under gospel library/additional addresses/CES addresses).