Ether 5:2 refers to those “that ye [Joseph Smith] may show the plates unto,” specifically the Eight Witnesses. Verses 3–4 refer to “three” who would see the plates “by the power of God,” which is a specific reference to the Three Witnesses of the Book of Mormon. Verse 4 also states that the word “shall stand as a testimony,” showing that the Book of Mormon itself is a witness. This same verse also shows that the Godhead are witnesses of the Book of Mormon.
Ether 5:2–4 specifically refers to the Three Witnesses of the Book of Mormon. In June of 1829 the Prophet Joseph Smith received a revelation “that three special witnesses would be designated. See Ether 5:2–4; also 2 Nephi 11:3 and 27:12. Oliver Cowdery, David Whitmer, and Martin Harris were moved upon by an inspired desire to be the three special witnesses” (D&C 17, section introduction). We have the testimony of the Three Witnesses in the introductory pages of the Book of Mormon. Of these Three Witnesses, Elder Dallin H. Oaks of the Quorum of the Twelve Apostles stated:
“The solemn written testimony of three witnesses to what they saw and heard—two of them simultaneously and the third almost immediately thereafter—is entitled to great weight. Indeed, we know that upon the testimony of one witness great miracles have been claimed and accepted by many religious people, and in the secular world the testimony of one witness has been deemed sufficient for weighty penalties and judgments.
“Persons experienced in evaluating testimony commonly consider a witness’s opportunity to observe an event and the possibility of his bias on the subject. Where different witnesses give identical testimony about the same event, skeptics look for evidence of collusion among them or for other witnesses who could contradict them.
“Measured against all of these possible objections, the testimony of the Three Witnesses to the Book of Mormon stands forth in great strength. Each of the three had ample reason and opportunity to renounce his testimony if it had been false or to equivocate on details if any had been inaccurate. As is well known, because of disagreements or jealousies involving other leaders of the Church, each one of these three witnesses was excommunicated from The Church of Jesus Christ of Latter-day Saints by about eight years after the publication of their testimony. All three went their separate ways, with no common interest to support a collusive effort. Yet to the end of their lives—periods ranging from 12 to 50 years after their excommunications—not one of these witnesses deviated from his published testimony or said anything that cast any shadow on its truthfulness.
“Furthermore, their testimony stands uncontradicted by any other witnesses. Reject it one may, but how does one explain three men of good character uniting and persisting in this published testimony to the end of their lives in the face of great ridicule and other personal disadvantage? Like the Book of Mormon itself, there is no better explanation than is given in the testimony itself, the solemn statement of good and honest men who told what they saw. …
“… Witnesses are important, and the testimony of the Three Witnesses to the Book of Mormon is impressive and reliable” (in Conference Report, Apr. 1999, 46, 49; or Ensign, May 1999, 35–37).