Had The Holy Book of Mormon been the keystone of the Mormon Church they would not be under the curse of condemnation these many years for not following its teachings:
54 And your minds in times past have been darkened because of unbelief, and because you have treated lightly the things you have received—
55 Which vanity and unbelief have brought the whole church under condemnation.
56 And this condemnation resteth upon the children of Zion, even all.
57 And they shall remain under this condemnation until they repent and remember the new covenant, even the Book of Mormon and the former commandments which I have given them, not only to say, but to do according to that which I have written—(D&C 84)
President Benson said the whole Church was still under that curse of condemnation:
“Unless we read the Book of Mormon and give heed to its teachings, the Lord has stated in section 84 of the Doctrine and Covenants that the whole Church is under condemnation: ‘And this condemnation resteth upon the children of Zion, even all.’ (D&C 84:56, 1832)”
“Why? The Lord answers: “That they may bring forth fruit meet for their Father’s kingdom; otherwise there remaineth a scourge and judgment to be poured out upon the children of Zion.” (D&C 84:58, 1832) We have felt that scourge and judgment!”
“We must first cleanse the inner vessel by awaking and arising, being morally clean, using the Book of Mormon in a manner so that God will lift the condemnation, and finally conquering pride by humbling ourselves.” (Ezra Taft Benson, Ensign, May, 1986, p. 4)