Sidney Rigdon was a respected 33 year old Baptist minister and preacher when for Latter Day Saints missionaries came with the Book of Mormon. Rigdon was Parly Pratts former minister and mentor, and Pratt hope that Rigdon would recognize the Book of Mormon as the word of God. At first, Rigdon was skeptical. His daughter said he did not believe a word of it. When he first heard about it and others reported he partially condemned it. However, as his son later remembered that when Rigdon was given a copy of the book, he got so engaged in with it that it was hard for him to quit long enough to eat his meals.
He read it day and night. After learning that Joseph had hardly a common school education, Rigdon was convinced Joseph had not written the Book of Mormon. He expressed the utmost amazement that such a man should write a book which seemed to shed a flood of light on all the old scriptures, open their profoundest mysteries and give them perfect consistency and complete system. Thus, he reasoned, if God ever gave a revelation. Surely this must be divine.
Rigdon personally sought divine confirmation of the book’s veracity and received a vision in which he was shown the corruption of various religious teachings. Then, in his vision, Rigdon saw the Book of Mormon and it was pure as an angel. This was a testimony from God that the Book of Mormon was a divine revelation. In the following months and years, Rigdon faithfully assisted Joseph in a variety of capacities as directed by Revelation. Later in life, Rigdon persisted in bearing witness to the Book of Mormons divine authenticity.
His son said that he maintained this view right up until his death in 1876. Each of Reagan’s other children likewise insisted that this was absolutely true. Whatever imperfections Sidney Rigdon had, he was a defender of the divine truthfulness of the Book of Mormon from the time he became converted until his dying breath. He deserves gratitude from believers today for his many important and dedicated contributions in building up of the Kingdom of God during the earliest years of the restoration and also for his unwavering testimony of the Book of Mormon.
And now you know why.