This is one of the great missionary scriptures. It is used to show the Book of Mormon already anticipated an argument against it, and as a result shows there is no reason to reject the Book of Mormon because there is already an existing, recognized volume of scripture.
The gentiles are prone to prefer the Bible to the Book of Mormon. We emphasized the Book of Mormon for a few years, but found that other faiths were critical because we were not using the Bible as we should. So there has been a conscious effort to re-emphasize the Bible and de-emphasize the Book of Mormon. This has been done to broaden our appeal to members of other faiths.
The gravamen of the argument is in the words: "there cannot be any more Bible." The idea there are other words of God, requiring equal respect to the words in the Bible, is a shocking heresy for many of the gentiles. Remember that first phrase in the first verse: "Behold there shall be many" who are going to say this. The "many" are the gentiles, and their criticism will be Bible-based.
So, how are we doing with this idea? Do we prefer the Biblical teachings to those of the Book of Mormon? Do we spend more time with the Bible than the Book of Mormon in our own individual study? If we had to choose one as the "standard for our people" which one would we choose? The Book of Mormon (as verse 2 suggests) or the Bible (as verse 3 suggests)? The Lord's standard is the Book of Mormon. The gentile standard will be the Bible. Once again we are at odds with Historic Christianity.
This is not to say we disrespect the Bible. We don't. We accept it as scripture. It is an admittedly valuable standard work, to be used in study and receiving knowledge of the things of God. Indeed, among other things the Book of Mormon testifies of the truth of the Bible. Therefore the Bible is certainly accepted as a work of importance and value to us in matters of faith. But only one can assume primacy. The primary one for us is the Book of Mormon.
We may be justified in our attachment to and affection for the Bible. But the Book of Mormon must be preeminent. Our respect and affection for the Doctrine and Covenants, Temple and church organization is also well placed and should inform our understanding and behavior. But the Book of Mormon was intended to be the primary means for the Lord to impart understanding to us.
Much has has been written and said about this volume of scripture, but we are only now beginning to understand what we are looking at.
In Eighteen Verses I have shown how little we have done so far with this book of scripture. I have never attempted to be exhaustive in any discussion about the book. In a decade of teaching weekly about the book, where I only went from 1 Nephi 1: 1 to Jarom 1: 4, the discussion was not exhaustive.
This book was a gift to us. We ought not think the Bible has more to offer than what we find in "the most correct book" because a "man can get closer to God by abiding the precepts [of the Book of Mormon] than any other book," just as Joseph Smith said.
The primary text of scripture I have used in The Second Comforter, Nephi's Isaiah and Eighteen Verses has been the Book of Mormon. The primary text used in this blog is the Book of Mormon.
Until we understand that book, I fail to see why we think we should have more. There is more in that book than we've noticed. The first step ought be to notice what we have. Then things will be added. However, until we have taken the Book of Mormon seriously, I fail to see why the most important message for us --found within that book-- should not be the first thing to be understood.