Two Book of Mormon passages prophesy that “three witnesses” (2 Nephi 27:12) “shall assist to bring forth this work” and would be shown the Book of Mormon plates so they could know and bear witness of the truth (Ether 5:2–3). Joseph translated the passage in Ether first. By the time he translated the 2 Nephi prophecy, he was nearly finished with the Book of Mormon, and there had been plenty of foreshadowing about who the three “who shall assist” could be.

In section 5 the Lord had told Martin Harris that he could qualify if he chose to be humble and faithful. In section 6 the Lord mentioned witnesses and testimony and told Oliver Cowdery that he should “assist to bring forth my work” (D&C 6:9, 28, 31). In section 14 the Lord called David Whitmer “to assist” and prophesied that if he asked of God in faith he would “stand as a witness of the things which you shall both hear and see” (D&C 14:8, 11).

In June 1829, as the translation neared completion at the Whitmers’ home in Fayette, New York, Martin, David, and Oliver pled with Joseph to ask God if they could be the prophesied witnesses. Joseph asked and the Lord answered with section 17. Joseph rose from his knees and said to Martin, “You have got to humble yourself before God this day and obtain, if possible, a forgiveness of your sins. If you will do this, it is God's will that you and Oliver Cowdery and David Whitmer should look upon the plates.”[1]

The revelation can be read as a covenant in which the Lord promises Oliver, David, and Martin that if they will rely on his word wholeheartedly, he will show them the Book of Mormon plates, the breastplate, Laban’s sword, the seer stones the Lord made for the brother of Jared, and the Liahona that directed Lehi and his family miraculously through the wilderness near the Red Sea. The witnesses would view these artifacts by faith like that of the brother of Jared or Lehi.

That witness would prove to these men much more than the fact that Joseph had plates. Lehi's miraculous compass, Laban's sword, and the brother of Jared's seer stones testify that the plates were inscribed with ancient writing about actual people who received revelations, knew the Lord, were directed to a promised land, and committed their testimonies of Christ to writing that had been translated by Joseph Smith.

In exchange for such an experience, the Lord obligated the would-be witnesses to testify of the Book of Mormon to fulfill his purposes. Their witness would verify Joseph's, keep him from being overwhelmed, and accomplish the Lord's righteous purposes. On these conditions, the Lord covenanted to resurrect the witnesses at the time of his second coming.

About noon on a late spring day in 1829, Joseph, David, Oliver, and Martin slipped into the woods near the Whitmer home. “Having knelt down,” Joseph said, “we began to pray in much faith, to Almighty God, to bestow upon us a realization of those promises. According to previous arrangement, I commenced by vocal prayer to our Heavenly Father and was followed by each of the other three.” Nothing happened.

“We again observed the same order of prayer, each calling on and praying fervently to God in regular rotation, but with the same result as before.” Finally, Martin Harris confessed that he was responsible for the Lord's silence. He left the others humbly, disappearing deeper into the woods. “We knelt down again,” Joseph stated, “and had not been many minutes engaged in prayer when presently we beheld a light above us in the air of exceeding brightness and behold an angel stood before us.” He held out the plates for them to see, turning them over one by one. “We could see them,” Joseph testified, “and discern the engravings thereon very distinctly.” A heavenly voice declared, “These plates have been revealed by the power of God, the translation of them which you have seen is correct, and I command you to bear record of what you now see and hear.”

“I left David and Oliver,” Joseph reported, “and went in pursuit of Martin Harris, whom I found at a considerable distance fervently engaged in prayer.” Joseph knelt beside him and their joined faith opened heaven. Joseph saw and heard the vision again while Martin cried out, “Mine eyes have beheld, mine eyes have beheld,” and was overcome with joy. Joseph helped him up and they returned to the Whitmer home, rejoicing.[2]

Joseph entered the room where his parents and Mrs. Whitmer were visiting. “Father! Mother! You do not know how happy I am. The Lord has caused the plates to be shown to three more besides me. They have also seen an angel and will have to testify to the truth of what I have said, for they know for themselves that I do not go about to deceive the people.” The pressure of being the sole eyewitness had, Joseph said, become “almost too much for me to endure. But they will now have to bear a part, and it does rejoice my soul that I am not any longer to be entirely alone in the world.”[3]

Martin, Oliver, and David eagerly told what they had seen and heard. They wrote a statement of testimony to the whole world that they had seen the engraved plates and heard the voice of God state that they were translated correctly. “We declare with words of soberness,” they affirmed, “that an angel of God came down from heaven, and he brought and laid before our eyes, that we beheld and saw the plates, and the engravings thereon.” It happened just as all the witnesses said. “It is marvelous in our eyes,” they declared together. “Nevertheless, the voice of the Lord commanded us that we should bear record of it; wherefore, to be obedient unto the commandments of God, we bear testimony of these things.”[4]

As Section 17 emphasizes, the witnesses fulfill the Lord's righteous purposes. They do not compel people to believe. They make everyone able to accept or reject the testimony and accountable for their choice. Witnesses sift people into self-selected categories of believers or unbelievers. “Their testimony shall . . . go forth unto the condemnation of this generation if they harden their hearts,” while those who believe will receive the testimony of the Spirit (D&C 5:5–6).