B. H. Roberts speaks to BOM's divinity and prophetic qualities.
B.H. Roberts, Speech, April 1930, in One Hundredth Annual Conference of the Church of Jesus Christ of Latter-day Saints (Salt Lake City: The Church of Jesus Christ of Latter-day Saints, 1930), 41–49
The Church of Jesus Christ has again, and for the last time, been set up and made the depository of God's truth and the fulness of it ; and has been given the missiqn of proclaiming that truth and the fulness of it to every nation and kindred and tongue and people. Also to this Church has been given the high mission of perfecting the lives of those who receive its truth.
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The Record of Joseph in the hands of Ephraim, the Book of Mormon, has been revealed and translated by the power of God, and supplies the world with a new witness for the Christ, and the truth and the fulness of the Gospel.
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And these things will increase more and more. And while, as the prophets of the Book of Mormon foresaw, the possession of the saints upon the land of promise would be few, and scattered upon all the face of the promised land (I Nephi, chapter xiv:12), yet will they be multiplied until they shall become a mighty people; and from among them will arise those who shall be able to move in upon and redeem Zion, the centerplace thereof, and fulfill God's word and purposes as to the mission of the capital city of the Christ's spiritual, growing empire in America.