4 Remember ye the law of Moses, my servant, which I commanded unto him in Horeb for all Israel, with the statutes and judgments.
5 Behold, I will send you Elijah the prophet before the coming of the great and dreadful day of the Lord;
6 And he shall turn the heart of the fathers to the children, and the heart of the children to their fathers, lest I come and smite the earth with a curse.
(3 Nephi 25:4-6)
After expounding (presenting and explaining in detail) “all the scriptures in one” (3 Nephi 23:14), Jesus shared some additional scripture–two chapters “which the Father had given unto Malachi” (3 Nephi 24:1). These happen to be the same two chapters which the angel Moroni quoted to Joseph Smith in 1823 as the first of many quotations from the Bible (Joseph Smith-History 1:36-39).
Interestingly, in this passage, Malachi refers to two other prophets who had lived many years before him: Moses and Elijah. He refers to Moses in the past tense, encouraging us to follow the commandments which Moses received at Mount Horeb. Then he prophesies that Elijah would come to turn the hearts of parents and children to one another. During the Savior’s mortal ministry, both Moses and Elijah appeared to Him on the Mount of Transfiguration to strengthen Him. And in 1836, they both appeared to the prophet Joseph Smith in the Kirtland temple to give him priesthood keys.
It seems clear to me that the Savior wants us to understand that God speaks with one voice through His prophets, even across generations. President Henry B. Eyring encouraged seminary teachers to help their students understand this principle:
I would try to help them feel the Savior as unchangeable, the same God who speaks to them through the Old and New Testament, the Book of Mormon, the Doctrine and Covenants, the Pearl of Great Price, and through his living prophets. He is not exacting one place and forgiving another. He is always both because he loves us and knows what we must have to receive the gift he offers us (“Covenants and Sacrifice,” CES Symposium on the Old Testament, 15 August 1995, Brigham Young University).
Today, I will remember that God speaks with one voice through many messengers. I will be grateful for the simple message of the gospel which has been consistently taught by prophets throughout the generations.