The Tetragrammaton is correctly pronounced Jehovah, as it is rendered in the Authorized Version (Exodus 6:3; Psalm 83:18; Isaiah 12:2, etc.). A previous post discussed some of the evidence for this fact, but did not elaborate on the meaning of the Name. Revelation 1:4-5, explains the significance of the Tetragrammaton as oJ w·n kai« oJ h™n kai« oJ e˙rco/menoß, ho on kai ho en kai ho erchomenos, “He who is, and who was, and who is to come.” Likewise, the Hebrew Yehowah (hODwh◊y) is the fusion of yehi howeh hawah (hÎwDh hRwøh yIh◊y), “He was” (Qal perf 3ms) “He is” (Qal part ms) “He will be (Qal impf 3ms [same as juss]),” into one word, as recognized by a number of modern scholars, such as “Hölemann in his Bibelstudien . . . in common with Stier and others.” The vocalization Jehovah, unlike the corrupt modern alternative Yahweh, thus properly represents the eternal self-existence of the one true God and is in accordance with the inspired explanation of Revelation 1:4-5, 8. Wilhelmus a Brakel explains the classical interpretation of the significance of Yehowah or Jehovah as follows:
[I]t has pleased the Lord to give Himself a name by which He wishes to be called—a name which would indicate His essence, the manner of His existence, and the plurality of divine Persons. The name which is indicative of His essence is hDOwh◊y or Jehovah, it being abbreviated as hDy or Jah. The name which is indicative of the trinity of Persons is MyIhølTa or Elohim. Often there is a coalescence of these two words resulting in hIwøhTy or Jehovi. The consonants of this word constitute the name Jehovah, whereas the vowel marks produce the name Elohim. Very frequently these two names are placed side by side in the following manner: Jehovah Elohim, to reveal that God is one in essence and three in His Persons.
The Jews do not pronounce the name Jehovah. This practice of not using the name Jehovah initially was perhaps an expression of reverence, but later became superstitious in nature. In its place they use the name yÎnOdSa or Adonai, a name by which the Lord is frequently called in His Word. Its meaning is “Lord.” When this word is used in reference to men, it is written with the letter patach, which is the short “a” vowel. When it is used in reference to the Lord, however, the letter kametz is used, which is the long “a” vowel. As a result all the vowels of the name Jehovah are present. To accomplish this the vowel “e” is changed into a chatef-patach which is the shortest “a” vowel, referred to as the guttural letter aleph. Our translators, to give expression to the name Jehovah, use the name Lord, which is similar to the Greek word ku/rioß (kurios), the latter being a translation of Adonai rather than Jehovah. In Rev 1:4 and 16:5 the apostle John translates the name Jehovah as follows: “Him which is, and which was, and which is to come.” This one word has reference primarily to being or essence, while having the chronological connotation of past, present, and future. In this way this name refers to an eternal being, and therefore the translation of the name Jehovah in the French Bible is l’Eternel, that is, the Eternal One. . . Jehovah is not a common name, such as “angel” or “man”—names which can be assigned to many by virtue of being of equal status. On the contrary, it is a proper Name which uniquely belongs to God and thus to no one else, as is true of the name of every creature, each of which has his own name. (pgs. 84-85, The Christian’s Reasonable Service, vol. 1)
Regrettably, the critical Hebrew text very frequently corrupts the Hebrew Yehowah or Jehovah into Yeh-wah, contrary to the true meaning of the Name and the preserved Hebrew Textus Receptus. If we use a corrupt modern Bible version translated from an inferior Hebrew text, let us set it aside for the Authorized Version. When we see the word “Jehovah” in the Authorized Version, or see “LORD” or “GOD” in all capitals, let us think on the glorious self-existence of the covenant-keeping Jehovah, and be stirred up to give Him the holy reverence and love that He so richly deserves.
For more on the subject of the Hebrew vowel points, please read the essays on the subject here. More specifics on the validity of the name Jehovah is here.