WWP letter to his wife saying he heard JS preach.
William W. Phelps to Sally Phelps, June 2, 1835, 4, The Joseph Smith Papers website, accessed August 11, 2021
President Smith preached last Sabbath, and I gave him the text: ‘This is my belovd Son; hear ye him!’ He preached one of the greatest sermons I ever heard—it was about 3½ hours long—and unfolded more mysteries than I can write at this time.