19. (1) The one God is called Jehovah from Esse, that is, because He alone Is, Was, and Is To Be, and because He is the First and the Last, the Beginning and the End, the Alpha and the Omega. It is known that "Jehovah" signifies I Am and To Be [Esse]; and that God has been so called from the most ancient times is clear from the Book of Creation, or Genesis, where in the first chapter He is called "God," and in the second and subsequent chapters "Jehovah God," and afterwards, when the children of Abraham through Jacob, during their long sojourn in Egypt, forgot the name of God, it was recalled to their remembrance; of which as follows:
Moses said unto God, What is Thy name? God said unto Moses, I am who I Am, thus shalt thou say unto the children of Israel, I Am hath sent Me unto you; and thou shalt say, Jehovah God of your fathers hath sent Me unto you: this is My name to eternity, and this is My memorial from generation to generation (Exod. 3:13-15).
Since God alone is the I Am and Esse, or Jehovah, nothing can exist in the created universe that does not derive its esse from Him; but how will be seen below. The words:
I am the First and the Last, the Beginning and the End, the Alpha and the Omega (Isa. 44:6: Rev. 1:8, 11; 22:13),
have the same meaning, signifying, Who is the Itself and the Only from things first to things last, the source of all things.  God is called "the Alpha and the Omega, the Beginning and the End," because Alpha is the first letter in the Greek alphabet and Omega the last; and therefore the two signify all things in the complex. This is because each letter in the alphabet in the spiritual world signifies a thing. And as the vowels furnish the tone, they signify something belonging to affection or love. This is the origin both of spiritual or angelic speech and of writing there. But it is an arcanum hitherto unknown; for there is a universal language which is the language of all angels and spirits, and which has nothing in common with any language of men in the world; into this language everyone comes after death, for it is inherent in every man from his creation; consequently in the spiritual world everyone can understand every other. I have frequently been permitted to hear that language; and I have compared it with languages in the world, and have found that in no respect whatever does it agree with any natural language on earth. It differs from them in its initial element, which is that each letter in each word has its special meaning. It is for this reason that God is called Alpha and Omega, which means that He is the Itself and the Only from things first to things last, the source of all things. But regarding this speech and form of writing, which flows from the spiritual thought of the angels, see the work on Conjugial Love (n. 326-329) also in the following pages.