In verse 9 we learn that the unsealed portion of the Book of Mormon will be translated. To accomplish this the entire record will be delivered to a man, who turns out to be Joseph Smith. Then Nephi observed that Joseph Smith will not turn the record over to another person -- who turns out to be Martin Harris -- but he will only give him the words or transcription of characters from the unsealed portion of the plates, together with the inspired translation thereof. In verse 10 Nephi emphasizes that Joseph Smith will not give Martin Harris either the sealed part of the record nor the record itself, only the characters or words copied from the record and the translation.
In verse 12 Nephi reveals an exciting aspect of the coming forth of the Book of Mormon. He said there will be three people besides Joseph Smith who will get to see this sacred record and hear the declaration of God himself that it is true. It is this twelfth verse which seems to have induced three of Joseph Smith’s associates to later plead for the privilege of being these three special witnesses to the reality of this sacred record. The Lord responded to their plea and these three turned out to be Oliver Cowdery, David Whitmer and Martin Harris. The brief biography of each of Three Witnesses is set forth in Treasures from the Book of Mormon, volume one beginning on page 275.
What happened to these men when they were allowed to become special witnesses is described by David Whitmer as recorded in a book by Preston Nibley, entitled, The Witnesses of the Book of Mormon. In this book we are told that when Joseph and the Three Witnesses first prayed to the Lord, nothing happened. Finally Martin Harris, who had lost the first 116 pages of the translation, felt the Lord was still offended by him and therefore he separated himself a considerable distance so he could continue to plead with the Lord for forgiveness.
After Martin Harris departed, David Whitmer says: “Joseph and Oliver and I were sitting on a log when we were overshadowed by a light more glorious than that of the sun. In the midst of this light, but a few feet from us, appeared a table upon which were many golden plates, also the sword of Laban and the directors [the Liahoma]. I saw them as plain as I see you now, and distinctly heard the voice of the Lord declaring that the records of the plates of the Book of Mormon were translated by the gift and power of God.” The angel stood by the table and invited the witnesses to examine each of the Nephite artifacts.
David Whitmer then described the gold plates. He said: “They appeared to be of gold, about six by nine inches in size, about as thick as parchment, a great many in number, and bound together like the leaves of a book by massive rings passing through the back edges.”
1 When the vision was over, Joseph went to find Martin Harris and began praying with him. Very shortly the same vision appeared again. Martin Harris later stated that the angel stood on the opposite side of the table on which were the plates, the sword of Laban, the interpreters, etc. Martin Harris took the plates in his hands and turned the sheets one by one. The angel declared that the Book of Mormon was correctly translated by the power of God and not of man, and that it contained the fulness of the gospel of Jesus Christ to the Nephites.
2 Joseph returned to the house and his mother says “Joseph threw himself down beside me, and exclaimed, ’Father, mother, you do not know how happy I am; the Lord has now caused the plates to be shown to three more beside myself. They have seen an angel, who has testified to them, and they will have to bear witness to the truth of what I have said.”