Jehovah
The covenant or proper name of the God of Israel. It denotes “the eternal I Am” (Ex. 3:14; John 8:58). Jehovah is the premortal Jesus Christ and came to earth as a son of Mary (Mosiah 3:8; 15:1; 3 Ne. 15:1–5). Usually, when the word Lord appears in the Old Testament, it means “Jehovah.”
Jehovah is Christ
Jehovah was known to the ancient prophets (Ex. 6:3; Abr. 1:16). The Apostle Paul taught that Christ was the Jehovah of the Old Testament (Ex. 17:6; 1 Cor. 10:1–4). The brother of Jared in the Book of Mormon saw the premortal Christ and worshiped Him (Ether 3:13–15). Moroni also called Christ “Jehovah” (Moro. 10:34). At the Kirtland Temple, Joseph Smith and Oliver Cowdery saw the resurrected Jehovah (D&C 110:3–4).