The name “Jehovah” only appears in the Old Testament four times (Gen 22:14, Ex 6:3, Ps 83:18, Isa 12:2) and once in an abbreviated form, JAH (Ps 68:4). The first of these examples demonstrates that the “Lord” of the Old Testament is, in fact, Jehovah. ’And Abraham called the name of that place Jehovah-jireh: as it is said to this day, In the mount of the Lord it shall be seen’ (Gen 22:14). Obviously this means that the God of Abraham, Isaac and Jacob is none other than Jehovah, the pre-mortal Jesus Christ. The fact that “Jehovah” is a name for the pre-mortal Christ is clear to latter-day saints. This comes from teachings in latter-day scriptures and the temple. To the rest of the world, it is less obvious and a source of misunderstanding. With some work, one can demonstrate, using only the Bible, that the God of the Old Testament is the same individual as Jesus Christ. Comparing the following pairs of scriptures will be helpful: Ex 3:13 and Jn 8:58; Isa 6:8-11 and Jn 12:40-1; and Zech 12:10 and Jn 19:37. See also Jn 1:1-3,14. Using the Book of Mormon the connection is easy to make for when Christ appeared to the Nephites he declared, ’Behold, I say unto you that the law is fulfilled that was given unto Moses. Behold, I am he that gave the law, and I am he who covenanted with my people Israel’ (3 Nephi 15:4-5). He also said, ’Behold I am Jesus Christ the Son of God. I created the heavens and the earth, and all things that in them are. I was with the Father from the beginning’ (3 Nephi 9:15).
James E. Talmage
"We claim scriptural authority for the assertion that Jesus Christ was and is God the Creator, the God who revealed Himself to Adam, Enoch, and all the antediluvial patriarchs and prophets down to Noah; the God of Abraham, Isaac and Jacob... We affirm that Jesus Christ was and is Jehovah, the Eternal One….
"Jesus is the individual name of the Savior, and as thus spelled is of Greek derivation; its Hebrew equivalent was Yehoshua or Yeshua, or, as we render it in English, Joshua. In the original the name was well understood as meaning ’Help of Jehovah,‘ or ’Savior.’…
"Jehovah is the Anglicized rendering of the Hebrew, Yahveh or Jahveh, signifying the Self-existent One, or The Eternal. This name is generally rendered in our English version of the Old Testament as LORD, printed in capitals. The Hebrew, Ehyeh, signifying I Am, is related in meaning and through derivation with the term Yahveh or Jehovah, and herein lies the significance of this name by which the Lord revealed Himself to Moses when the latter received the commission to go into Egypt and deliver the children of Israel from bondage…
"The Jews regarded Jehovah as an ineffable name, not to be spoken; they substituted for it the sacred, though to them the not-forbidden name, Adonai, signifying the Lord. The original of the terms Lord and God as they appear in the Old Testament, was either Yahveh or Adonai; and the divine Being designated by these sacred names was, as shown by the scriptures cited, Jesus the Christ. John, evangelist and apostle, positively identifies Jesus Christ with Adonai, or the Lord who spoke through the voice of Isaiah, and with Jehovah who spoke through Zechariah.…
"‘Jehovah’ a Name Not Uttered by the Jews. -- Long prior to the time of Christ, certain schools among the Jews, ever intent on the observance of the letter of the law, though not without disregard of its spirit, had taught that the mere utterance of the name of God was blasphemous, and that the sin of so doing constituted a capital offense. This extreme conception arose from the accepted though uninspired interpretation of Lev. 24:16, ’And he that blasphemeth the name of the Lord, he shall surely be put to death, and all the congregation shall certainly stone him: as well the stranger, as he that is born in the land, when he blasphemeth the name of the Lord, shall be put to death.’ (Jesus the Christ, pp. 32-41)
At Jacob’s well, Jesus made an offer to the woman from Samaria, ’If thou knewest the gift of God, and who it is that saith to thee, Give me to drink; thou wouldest have asked of him, and he would have given thee living water…whosoever drinketh of the water that I shall give him shall never thirst; but the water that I shall give him shall be in him a well of water springing up into everlasting life.’ (John 4:10-14) The Samaritan woman thought he spoke of literal water, but in the Millenial day, the spiritual thirst of the House of Israel will be quenched for they will draw living ’water out of the wells of salvation.’
“The Lord provides the living water that can quench the burning thirst of those whose lives are parched by a drought of truth. He expects us to supply to them the fulness of the gospel by giving them the scriptures and the words of the prophets and to bear personal testimony as to the truth of the restored gospel to alleviate their thirst. When they drink from the cup of gospel knowledge, their thirst is satisfied as they come to understand our Heavenly Father’s great plan of happiness.” (“Living Water to Quench Spiritual Thirst,” Ensign, May 1995, 19)