YHWH: The Eternal first introduced His name as YHWH (LORD) in Exodus 3 where Moses records the account of receiving his commission from God. In verse 15 God calls Himself YHWH Elohim translated "LORD God" in most English-language Bibles. In the Authorized Version, wherever we find the name "GOD" or "LORD " printed in small capitals, the original is YHWH (see Genesis 2:4-5, 7-8).
The original Hebrew text consists of consonants only and no vowels, and thus the Creator's name is spelled YHWH. This is often referred to as the tetragrammaton, meaning the "four letters." YHWH derives from a form of the Hebrew verb to be and has the same meaning as the name "I AM" (hayah) in Exodus 3:14. Hebrew scholars say YHWH could mean "He exists" or "He causes to be." English equivalents to this would be "the Ever-Living" or "the Eternal." God and His name are both everlasting (Psalm 135:13). The meaning of the name and the permanency behind it are crucial to properly recognizing His sovereignty.
Scholars believe that YHWH was originally pronounced as Yahweh, but we have no concrete evidence of what the missing vowels should be. The Jews considered YHWH too sacred to speak, so they stopped pronouncing it after the days of Ezra and Nehemiah, when it was considered unlawful and blasphemous to vocalize it. The correct pronunciation was forgotten over time. When a Jew recites scripture and comes to YHWH, he substitutes the word Adonai, meaning "Lord" or "Master." Therefore, the name of God is written YHWH but pronounced Adonai.
Some have thought YHWH should be pronounced "Jehovah." In AD 1520, Peter Galatin, the confessor of Pope Leo X, invented this name by interjecting the vowels of Adonai (a-o-a) between the consonants YHWH. This produced the hybrid YaHoWaH, later pronounce "Jehovah." This name, contrived through human reasoning, has no biblical basis.
Martin G. Collins
The Names of God