Where can I find the account of when Joseph and Samuel Smith went into a room in the hill Cumorah and saw the sword of Laban and the plates that the Book of Mormon was abridged from?

Dear Gramps,
Where can I find the account of when Joseph and Samuel Smith went into a room in the hill Cumorah and saw the sword of Laban and the plates that the Book of Mormon was abridged from?
Deborah, from Derby, England

Dear Deborah,

It was Joseph Smith and Oliver Cowdery who returned the plates from which the Book of Mormon was translated back to the hill Cumorah. One source of what you search for is quoted by Brigham Young, and recorded in the Journal of Discourses, vol. 19:, p.39–

Oliver Cowdery went with the Prophet Joseph when he deposited these plates. Joseph did not translate all of the plates; there was a portion of them sealed, which you can learn from the Book of Doctrine and Covenants. When Joseph got the plates, the angel instructed him to carry them back to the hill Cumorah, which he did. Oliver says that when Joseph and Oliver went there, the hill opened, and they walked into a cave, in which there was a large and spacious room. He says he did not think, at the time, whether they had the light of the sun or artificial light; but that it was just as light as day. They laid the plates on a table; it was a large table that stood in the room. Under this table there was a pile of plates as much as two feet high, and there were altogether in this room more plates than probably many wagon loads; they were piled up in the corners and along the walls. The first time they went there the sword of Laban hung upon the wall; but when they went again it had been taken down and laid upon the table across the gold plates; it was unsheathed, and on it was written these words: “This sword will never be sheathed again until the kingdoms of this world become the kingdom of our God and his Christ.”

Gramps