Like modern members of The Church of Jesus Christ of Latter-day Saints, the ancient Israelites worshiped God under various names and titles. The covenant name of the God of Israel was composed of the letters YHWH, which was probably pronounced something like Yahweh or Yaho. This name comes into English through Latin as Jehovah. (This was definitively not the ancient pronunciation since Hebrew has no j sound and did not have a v sound in ancient times.) From an etymological perspective the name YHWH (or Jehovah) could mean something like “He Who Is,” “the Great I Am,” “the Self-Sustaining One,” or “the Self-Existing One.”
Throughout the biblical period, this name was used and pronounced by individuals like Moses, Deborah, and Nephi. Later in history, those who did not worship the God of Israel began using the name as a magic word, and so worshippers stopped pronouncing it to protect its sanctity. In reading the Bible, they replaced the divine name with the Hebrew title Adonai, meaning “lord.” When the King James Version translators translated the Old Testament, they preserved this tradition by rendering the divine name as “Lord.” It is useful to remember when reading the Old Testament that the ancient Israelites did not replace Yahweh with Lord but rather used the name regularly.
The other primary name of God in the Old Testament is Elohim, which was simply the common noun for god and which, based on other Semitic languages, could mean something like “strong,” “mighty,” or “the Mighty One.” Like our English word god, Elohim could be used to describe the covenant God of Israel as well as the gods that other nations worshipped. Although the word is marked with a plural ending, when used in reference to the God of Israel, it is construed as a singular noun (that is, it takes singular verbs and singular adjectives). As with English god, context determines how Elohim is being used.
Psalm 82:1 provides a useful example of this: “God [Elohim] standeth in the congregation of the mighty; he judgeth among the gods [Elohim].” The exact same word is used at the beginning and end of this verse, but in the first occurrence, it is a singular noun referring to the God of Israel while in the second, it is a plural noun referring to other gods.
Although in the Church of Jesus Christ today we use Elohim to refer to Heavenly Father and Jehovah (YHWH) to refer to Jesus Christ, there is no discernible difference between the two divine names in the Old Testament. While some authors show a preference for one or the other (for example, YHWH appears almost four hundred times in the book of Numbers, while Elohim appears less than thirty), the two names are usually used interchangeably—sometimes in the same verse. God does not appear to have revealed a detailed doctrine of the Godhead during Old Testament times (see Doctrine and Covenants 124:41), but the Joseph Smith Translation and the Book of Mormon make it clear that at least some individuals knew that salvation would come through the Only Begotten Son.
1 Samuel 2:2
1 Samuel 10:19
2 Samuel 6:2
2 Samuel 7:26
2 Samuel 15:25
1 Kings 3:5
1 Kings 8:61
Psalm 18:2, 31