What Book is Known as the "Great Sifter"?

President Ezra Taft Benson’s comments:

I have noted within the Church a difference in discernment, insight, conviction, and spirit between those who know and love the Book of Mormon and those who do not. That Book is a great sifter. (Ensign, December 1988, p. 4)

The Book of Mormon brings men to Christ through two basic means. First, it tells in a plain manner of Christ and His gospel. It testifies of His divinity and of the necessity for a Redeemer and the need of our putting trust in Him. . . . Second, the Book of Mormon exposes the enemies of Christ. It confounds false doctrines and lays down contention. (see 2 Ne. 3:12) It fortifies the humble followers of Christ against the evil designs, strategies and doctrines of the devil in our day. The type of apostates in the Book of Mormon are similar to the type we have today. God, with his infinite foreknowledge, so molded the Book of Mormon that we might see the error and know how to combat false educational, political, religious, and philosophical concepts of our time. (Ensign, January 1988, p. 3)

Two great American Christian civilizations—the Jaredites and the Nephites—were swept off this land because they did not ‘serve the God of the land, who is Jesus Christ’ (Ether 2:12) What will become of our civilization? (Ensign, November 1987, p. 7).