D. Michael Quinn argues that the concept of the Book of Mormon as a "sealed" book and slippery treasures reflects the 19th century magic world view.
D. Michael Quinn, Early Mormonism and the Magic World View, rev. ed. (Salt Lake City: Signature Books, 1998), 196
The Book of Mormon’s description of itself as a “sealed” book also had a magic meaning that extended from antiquity to early America. One biblical scholar wrote: “In the above examples [from magic literature] it is important to note some of the more common terms. You will find that things are ‘bound,’ ‘sealed,’ ‘charmed,’ etc. . . . The terminology is very old. To bind, to seal, to charm, or to tie in some fashion is the commonest way of talking about the overcoming of evil.” Written in New York or New Hampshire, Caleb Gilman’s 1708 magic manuscript noted: “But none that come before this Door can know those Magical Powers, so as to unlock their Secrets or hid Treasures, but such only as are deeply rooted in true Love & profound Humility; from all others they are fast bolted & sealed by that Power that none can open.”
Moreover, the title page described the Book of Mormon plates as having been “sealed by the hand of Moroni, and hid up unto the Lord.” This description echoed the folklore of buried treasure, as described by an author with no reference to Mormonism: “For, it developed, anyone who buries money always put a ‘seal’ on it by saying certain words [so that] if anyone except the person in possession of the ‘seal’ attempts to take it, they’ll be foiled by those unearthly beings—dog or cat or snake or other creatures chosen—whom the ‘seal’ has set to guard it.’
In fact, the Book of Mormon described a complaint common to treasure-seekers: “Yea, we have hid up our treasures and they have slipped away from us, because of the curse of the land.” These people “began to hide up their treasures in the earth; and they became slippery, because the Lord had cursed the land” (Hel. 13:35; Morm. 1:18, emphasis added). This reflected the treasure-digging language of early America, as the book May Martin shows. The 1835 novel described Vermont treasure-diggers who dreamed of “the prospects of another trial for the slippery treasure.” Book of Mormon phrasing was consistent with one scholar’s observation about American folklore of “slipping treasures” that “sink into the earth when something is wrong.”