President Lorenzo Snow testified on numerous occasions of a marvelous manifestation from the Holy Ghost soon after his baptism. While not going into detail, he used expressive enough language to convey that he had been shown in vision details related to the coming forth of the Book of Mormon, which contained the fullness of the gospel:
Having become convinced by reasoning, and by listening to the testimony of others who had received these principles, I became satisfied that it was my duty to experiment upon these principles, that I might be able to test the results. This I consequently did, and there followed the same testimony and the same experiences, so far as the knowledge of the divinity of these principles was concerned, as followed obedience to this Gospel as proclaimed by the apostles in former times. And this knowledge could not be disputed. It was not only acknowledged intellectually, but the inspiration of the Holy Ghost imparted to me a knowledge as physically and as demonstrative as that physical ordinance when I was immersed in the waters of baptism; that as I had passed through the atmosphere into the element of water, so my experience, knowledge and testimony was full and complete, so complete, indeed, that from that day till the present moment, through all of the vicissitudes of life through which I have passed, I have no more doubted the truth of these principles than I do now that I behold this audience, and I never can doubt it. As long as memory continues and reason shall assert its throne, I never can permit the powerful testimony and knowledge that was communicated to me to remain silent. It was revealed to me. The heavens were opened over my head, and the power of God and the life of the Holy Ghost descended and elevated my whole being, and gave me the most perfect knowledge that Jesus was the Son of God. It was not the result simply of opinion or belief, as is the case in many other things, but it was a knowledge far beyond that of belief or opinion. I knew that God had sent His angels and restored the fullness of the Gospel as taught in ancient times; that He sent angels to authorize Joseph Smith, and gave him authority to administer in the ordinances of the Gospel, and to promise the Holy Ghost to all who would be obedient.
Discourse given March 6, 1887, Brigham City, as cited in CD 1: 24; see also Millennial Star, Vol. 39, no. 16 (April 18, 1887), 242.