Exodus 3:13

And Moses said unto God, Behold, when I come unto the children of Israel and shall say unto them, The God of your fathers hath sent me unto you, and they shall say unto me, What is His name? what shall I say unto them? The name God Almighty was too general to distinguish the true God from the idols of Egypt, and therefore the inquiry for the name has the purpose of obtaining some expression on the part of God which would indicate His essence and the actual manifestation of the divine essence toward His people, by which they might understand and apprehend Him.