After receiving an ancient sacred text written on gold plates from an angel named Moroni, Smith needed to translate and publish the text, an operation he knew would cost a considerable amount of money that he did not have. He asked Martin Harris, a farmer he knew in Palmyra, to fund the project. Harris agreed and soon became a close associate of Smith’s. Harris worked as a scribe while Smith dictated a translation of the text written on the plates.
Harris’s wife Lucy, like many in Palmyra, was extremely skeptical that the plates even existed and thought that Smith’s real intention was to steal their family's money. In order to appease his wife, Harris asked Smith if he could at least bring the manuscript home and show it to his family to prove that the work they were doing was real and important. At first Smith refused to let Harris take the manuscript, but he eventually he agreed. Smith made Harris promise that he would only show the manuscript to his wife, his parents, his brother, and his sister-in-law. Harris agreed, but after he got home he started showing the manuscript to anybody who asked and soon it disappeared.
Smith was worried that Lucy Harris had stolen the manuscript in order to prove that he was a fraud. If he retranslated the section covered by the manuscript, she might produce the original translation and show that there were discrepancies between the original translation and the later one, which people might understand to mean that Smith was making the whole thing up.
Smith prayed for guidance about how to handle the situation and said that he had received a revelation from God that he should not retranslate that section of the text. He claimed that he was given another set of plates that related the same events that had been described in the lost manuscript. This solved his dilemma and allowed him to finish translating the Book of Mormon and prepare it for publication.