Joseph relates how he obtained the BOM plates.
Joseph Smith, History, 1838–1856, volume A-1 [23 December 1805–30 August 1834], 8, Joseph Smith Papers
At length the time arrived for obtaining the plates, the Urim and Thummin and the breastplate, In <On> the twenty second day of September, One thousand Eight hundred and twenty seven, having went as usual at the end of another year to the place where they were deposited, the same heavenly messenger delivered them up to me with this charge that I should be responsible for them. That if I should let them go carelessly or <through> any neglect of mine I should be cut off, but that if I would use all my endeavours to preserve them untill <he> (the messenger) called should call for them, they should be protected.