This name of God gives us an idea about the nature of God. “I AM” is a term that comes from the Hebrew word, hayah, which means, “to be”. The expression that is used to refer to God in the Old Testament is frequently translated, “Jehovah”, and in some versions, “the LORD.” YAHWEH is how hayah has traditionally been written in translations of the Bible because of the lack of vowels in the Hebrew language. So, references to God in the Hebrew Old Testament are using the word YAHWEH—that is to say, “He is”. The stress rests upon the deathlessness of this true God revealed in the Old Testament.
He is the one who “is” and therefore He can speak of Himself as, “I AM” or “I AM THAT I AM”. What we have in YAHWEH itself is a testimony to the undying nature of God. “He is” is a testimony to His self-existence. He is the living God; He is YAHWEH; He is I AM; He is the one who has life in Himself; He is deathlessness. God is immutable—unchangeable—because He has an undying nature.
If God were a person who could die, He could not be immutable. He could not make us promises, for He could not be sure of keeping them. Consequently, we know that since God is immutable, we can count on his promises because He does not change. He does not change because inherent to His being is the fact that He is a self-existing God who draws life from Himself.