Nephi recognized the similarities between himself, Jacob, and Isaiah. All three had been privileged to see the Savior, to witness portions of his mortal ministry, and to be given knowledge about how the house of Israel will be gathered home in the last days. Their combined witness declares that Jesus Christ is the Messiah, that the promises of the fathers given to the house of Israel will all be fulfilled, and that God lives, for they had all seen him. As Nephi declares, by the words of three, God hath said, I will establish my word.
Jeffrey R. Holland
“I am suggesting here that Nephi, Jacob, and Isaiah are three early types and shadows of Oliver Cowdery, David Whitmer, and Martine Harris, if you will—witnesses positioned right at the front of the book where Oliver, David, and Martin would be positioned—that Nephi, Jacob, and Isaiah are the three great ancient witnesses of the Book of Mormon—or more particularly, the first three great witnesses in the Book of Mormon testifying to the divinity of Jesus Christ, the Son of God, he who will be the central, commanding, presiding figure throughout the Book of Mormon. Nephi stresses this idea himself when he writes in the eleventh chapter of 2 Nephi: [verses 2-3].”