The Translation of the Book of Mormon
Joseph Smith—History 1:66–67
66 On the 5th day of April, 1829, Oliver Cowdery came to my house, until which time I had never seen him. He stated to me that having been teaching school in the neighborhood where my father resided, and my father being one of those who sent to the school, he went to board for a season at his house, and while there the family related to him the circumstances of my having received the plates, and accordingly he had come to make inquiries of me.
67 Two days after the arrival of Mr. Cowdery (being the 7th of April) I commenced to translate the Book of Mormon, and he began to write for me.
The Prophet Joseph Smith wrote:
“With the records was found a curious instrument, which the ancients called ‘Urim and Thummim,’ which consisted of two transparent stones set in the rim of a bow fastened to a breast plate. Through the medium of the Urim and Thummim I translated the record by the gift and power of God.”
(Teachings of Presidents of the Church: Joseph Smith [2007], 60.)