Mother Whitmer's vision of the golden plates

In 1829, while the translation of the Book of Mormon was underway at the home of Peter Whitmer Sr. in Fayette, New York, Mary Musselman Whitmer was overwhelmed by the labor required to care for her own large family along with Joseph and Emma Smith and Oliver Cowdery. According to accounts passed down through the family, Mary was often overworked and exhausted, feeling the heavy burden of hosting the extra guests. One evening, after completing her day's work, she went to the barn to milk the cows and was met by a stranger carrying a knapsack. Though initially afraid, she was comforted by his kind, friendly tone. The man, whom she later described as a heavenly messenger (often identified as the angel Moroni), explained the importance of the work occurring in her home. He untied his knapsack, showed her a bundle of golden plates, and turned the leaves one by one, displaying the engravings. He then encouraged her to be patient and faithful in bearing her burdens, promising that her reward would be sure. Following this vision, Mary felt strengthened and was able to perform her duties with ease, losing any inclination to murmur about her circumstances. While her grandson John C. Whitmer recalled her referring to the messenger as 'Brother Nephi,' researchers generally conclude she met the same heavenly messenger who delivered the plates to Joseph Smith, with her experience serving as a divine recognition of her quiet, essential service to the early Restoration.

Fuller account of this event (as retold in Mary Whitmer, 12th witness to the Book of Mormon – Deseret News):

And although she had never complained, she had sometimes felt that her labor was too much, or at least she was perhaps beginning to feel so. One day, though, probably in June 1829, when she was going out to milk the cows in the family barn — where, David happened to know, the plates were concealed at the time — she met an “old man,” as she described him, who said to her, in David’s account of the story, “You have been very faithful and diligent in your labors, but you are tired because of the increase of your toil; it is proper therefore that you should receive an witness that your faith may be strengthened.” Thereupon he took from his knapsack the plates and showed them to her. He turned the leaves of the book of plates over, leaf after leaf, and also showed her the engravings upon them; after which he told her to be patient and faithful in bearing her burden a little longer, promising that if she would do so, she should be blessed; and her reward would be sure, if she proved faithful to the end. The vision was a great comfort to her, and she was ever after able to perform her work with ease and cheerfulness.