"He [Joseph Smith] was a religious and straightforward man. He had to be; for he was illiterate and he could do nothing of himself. He had to trust in God. He could not translate unless he was humble and possessed the right feelings towards every one. To illustrate, so you can see. One morning when he was getting ready to continue the translation, something went wrong about the house and he was put out about it. Something that Emma, his wife, had done. Oliver and I went up stairs, and Joseph came up soon after to continue the translation, but he could not do anything. He could not translate a single syllable. He went down stairs, out into the orchard and made supplication to the Lord; was gone about an hour--came back to the house, asked Emma's forgiveness and then came up stairs where we were and the translation went on all right. He could do nothing save he was humble and faithful."
His statement concerning the vision they had of the plates and the angel was as follows: "I was plowing in the field one morning, and Joseph and Oliver came along with a revelation stating that I was to be one of the witnesses to the Book of Mormon. I got over the fence and we went out into the woods, near by, and sat down on a log and talked awhile. We then kneeled down and prayed. Joseph prayed. We then got up and sat on the log and were talking, when all at once a light came down from above us and encircled us for quite a little distance around; and the angel stood before us. He was dressed in white, and spoke and called me by name and said `Blessed is he that keepeth His commandments.' This is all that I heard the angel say. A table was set before us and on it the records were placed. The Records of the Nephites, from which the Book of Mormon was translated, the brass plates, the Ball of Directors, the sword of Laban and other plates. While we were viewing them the voice of God spoke out of heaven saying that the Book was true and the translation correct."
We then asked him, "Do you remember the peculiar sensation experienced upon that occasion?" He answered very slowly and definitely.
"Yes; I remember it very distinctly; and I never think of it, from that day to this but what that same spirit is present with me."
"How did you know it was the voice of God?"
"We knew it was the voice of God. I knew it was the voice of God just as well as I knew any thing."
[William H. Kelley to Saints' Herald, 16 January 1882, Saints' Herald 29 (1 March 1882): 68-69; reprinted in the Journal of History 3 (October 1910): 450-52., as cited in Dan Vogel, Early Mormon Documents: David Whitmer Interview With William H. Kelley And George A. Blakeslee]