Many members of the Church believe that Sidney Rigdon is the “spokesman” referred to in this prophecy. (2 Nephi 3:18.) It appears that Joseph Smith is the prophet mentioned in this verse, and the Lord promised Sidney Rigdon that he should “be a spokesman to my servant Joseph.” (D&C 100:9.) Elder George Q. Cannon explained as follows why he believed the calling of Sidney Rigdon as a spokesman for Joseph Smith was in direct fulfillment of this prophecy:
He [Sidney Rigdon] was baptized in the town of Kirtland, and the foundation of a great work was laid there. God afterwards revealed that this man was to be a spokesman, and he became the spokesman to this people and to the world for the prophet Joseph. Those who knew Sidney Rigdon, know how wonderfully God inspired him, and with what wonderful eloquence he declared the word of God to the people. He was a mighty man in the hands of God, as a spokesman, as long as the prophet lived, or up to a short time before his death. Thus you see that even this which many might look upon as a small matter, was predicted about 1,700 years before the birth of the Savior, and was quoted by Lehi 600 years before the same event, and about 2,400 years before its fulfillment, and was translated by the power of God, through his servant Joseph, as was predicted should be the case, and at a time, as I have said, when there was not a man upon the earth who was a member of The Church of Jesus Christ of Latter-day Saints. The church had not yet been organized, and Joseph did not know, unless he knew by the spirit of revelation, whether any man would receive the Gospel. (Journal of Discourses, 25:126-27.)