“And God spake unto Moses, and said unto him, I am the Lord: 3 and I appeared unto Abraham, unto Isaac, and unto Jacob, by the name of God Almighty, but by my name JEHOVAH was I not known to them.” (Exodus 6:2-3)

It would be tedious to recount the various opinions as to the name “Jehovah.” 

It is certainly a foul superstition of the Jews that they dare not speak, or write it, but substitute the name “Adonai;” nor do I any more approve of their teaching, who say that it is ineffable, because it is not written according to grammatical rule. 

Without controversy, it is derived from the word, hayah, or, havah, and therefore it is rightly said by learned commentators to be the essential name of God, whereas others are, as it were, epithets. 

Since, then, nothing is more peculiar to God than eternity, he is called Jehovah, because he has existence from himself, and sustains all things by his secret inspiration. 

Nor do I agree with the grammarians, who will not have it pronounced, because its inflection is irregular; because its etymology, of which all confess that God is the author, is more to me than an hundred rules. 

Nor does God by “his name” in this passage mean syllables or letters, but the knowledge of his glory and majesty, which shone out more fully and more brightly in the redemption of his Church, than in the commencement of the covenant. 

For Abraham and the other Patriarchs were content with a smaller measure of light; whence it follows that the fault of their descendants would be less excusable, if their faith was not answerable to the increase of their grace. 

Meanwhile, Moses is awakened to activity whilst God is setting before him a magnificent and singular means of shewing forth his glory.

Source: John Calvin, Commentaries on the Four Last Books of Moses Arranged in the Form of a Harmony, trans. Charles W. Bingham (Edinburgh: Calvin Translation Society, 1843), 127. [Read online, pg. 88]