William McLellin writes to James T. Cobb, says he recalls David Whitmer's testimony in the BoM, which he (McLellin) still believes.
William E. McLellin, Letter to James T. Cobb, August 14, 1880, in Stan Larson and Samuel J. Passey, eds., The William E. McLellin Papers, 1854–1880 (Salt Lake City, UT: Signature Books, 2007), 522
When I first joined the church in 1831, soon I became acquainted with all the Smith family and the Whitmer family, heard all their testimonies, which agreed in the main points; and I believed them then and I believe them yet. But don't believe the many stories (contradictory) got up since, for I individually know many of them are false.
My advice to you is cease your opposition and strife against the Book, and fight against wrong doing in professors: for you might just as well fight against the rocky mountains as the Book!!
David Whitmer has lost his thumb on his right hand several years ago, and cannot write. And he would not be willing to write much to a man who fights the Book of M. which he knows to be true. I saw him June 1879, and heard him bear his solemn testimony to the truth of the book—as sincerely and solemnly as when he bore it to me in Paris, Ill. in July 1831. I believed him then and still believe him. You seem to think he and I ought to come out and tell something-some darkness relative to that book. We should lie if we did, for we know nothing against its credibility or divine truth.