David Whitmer said that God gave Joseph the ability to translate the BOM through a stone in fulfillment of Isaiah 29.
David Whitmer, An Address to All Believers in Christ by a Witness to the Divine Authenticity of The Book of Mormon, (Richmond, MO: David Whitmer, 1887), 6
The people cannot understand why the Lord would bring forth his word from “a book (plates) that is sealed” and was buried in the ground by his ancient prophets on this land: and why He should have the words of the book delivered “to one that is learned,” telling him to read it, etc.; (see Isa. xxix) but the learned and wise men of the world could not read it; God gave to an unlearned boy, Joseph Smith, the gift to translate it by the means of a stone.