1) The Book of Mormon contains, as does the Bible, the fullness of the everlasting gospel.
The term, “fullness of the everlasting gospel,” deserves some explanation. The Book of Mormon does not deal with many crucial doctrinal topics including
1) The pre-mortal life.
2) The council in heaven, the war in heaven, the third of the hosts of heaven that were cast down.
3) The three degrees of glory.
4) Baptism for the dead or any other vicarious ordinances.
The conclusion that must be drawn is that these doctrines are not a necessary component of the “fullness of the everlasting gospel.” The fullness of the everlasting gospel contains all the principles, doctrines, and commandments required to “gain peace in this life and eternal salvation in the world to come.” No other scripture teaches about the power of the atonement of Jesus Christ as completely and clearly as does the Book of Mormon. This is the essence of the “good news” of the gospel. The message is best described in the words of the Savior, I bear record that the Father commandeth all men, everywhere, to repent and believe in me. And whoso believeth in me, and is baptized, the same shall be saved; and they are they who shall inherit the kingdom of God.” (3 Ne 11:32-33)
2) Moroni, then a glorified, resurrected being
One might wonder about the resurrection of Moroni, as he died well after the first resurrection associated with the resurrection of Christ when many bodies of the saints which slept arose (Matt 27:52). The term, “first resurrection” is used to describe two events, the resurrection associated with the resurrection of Christ (Mosiah15:21-23), and the resurrection associated with the Second Coming of the Lord (DC 76:64). Some have defined the “first resurrection” as the resurrection which begins at the resurrection of Christ and continues until the “first” resurrection associated with his Second Coming. That definition raises the possibility that some saints are being resurrected in the interval between those two great events. However, the only individuals known to have been resurrected during that time period are Moroni, Peter, and James. Each of these men “had special labors to perform in this day which necessitated tangible resurrected bodies.” (Mormon Doctrine, p.639)
3) A new and additional witness that Jesus Christ is the Son of the living God
Paul records, in the mouth of two or three witnesses shall every word be established. (2 Cor 13:1) This principle is taught in the ancient Law of Moses (Deut 17:6), is repeated by the Savior (Matt 18:16), and is taught again by Paul. It becomes the standard by which a defendant is accused or a fact is established. Therefore, the Lord provides a second witness of the divinity of Jesus Christ by giving us the Book of Mormon; know ye not that the testimony of two nations is a witness unto you that I am God… (2 Ne 29:8). A careful study of almost any important doctrinal principle will reveal that the doctrine is taught in two or three different sources, usually the Bible, the Book of Mormon, and the Doctrine & Covenants. Thus we see that the Lord abides the law that he gave to Moses. This principle also condemns those who reject the message having had more than one witness. (Alma 30:45)
4) The most correct of any book
Detractors of the Book of Mormon have often quoted this phrase as they point to changes in different editions of the Book of Mormon, punctuation or grammatical problems. The context of Joseph Smith’s statement in this regard is that a man can grow nearer to God by abiding by its precepts than by any other book. Therefore, it is doctrinally the most correct book on the earth. The spirit of revelation which emanates from its pages declares to all that Jesus is the Christ and that salvation comes through his name. In the Book of Mormon Symposium Series, George A. Horton, Jr. explains:
“When Joseph Smith said ‘the Book of Mormon was the most correct of any book on earth,’ it seems evident that he was not talking about grammar, punctuation, or spelling. He was referring to the clarity and depth of doctrine, to the mission and message of the book, to the spirit of inspiration that it fosters, to the divine desire that it sparks in the soul to make the ‘mighty change,’ and to the abiding love of the Lord that it brings into our hearts.”
President Benson has declared:
“I have a vision of homes alerted, of classes alive, and of pulpits aflame with the spirit of Book of Mormon messages. I have a vision of home teachers and visiting teachers, ward and branch officers, and stake and mission leaders counseling our people out of the most correct of any book on earth – the Book of Mormon. I have a vision of artists putting into film, drama, literature, music, and paintings great themes and great characters from the Book of Mormon. I have a vision of thousands of missionaries going into the mission field with hundreds of passages memorized from the Book of Mormon so that they might feed the needs of a spiritually famished world. I have a vision of the whole Church getting nearer to God by abiding by the precepts of the Book of Mormon. Indeed, I have a vision of flooding the earth with the Book of Mormon.” (Church News, 06/04/94)