What did God tell Moses to say to the children of Israel at the burning bush?
At the burning bush, God instructed Moses to tell the children of Israel that I AM hath sent you, the I AM that I AM. This revealed the name Yahweh as the eternal, preexistent I AM who sent Moses to Israel.
Les explains that Moses anticipated the children of Israel would ask God's name, and the voice from the burning bush told him to say, “I AM hath sent you.” The I AM that I AM was the definition of Yahweh, the eternal, preexistent I AM. Les also notes that Jehovah comes from two Hebrew terms, Yahweh and Havah. Havah meant “the I AM is to be revealed,” a continuing-action type of verb, so the eternal, preexistent I AM would be revealed more and more as human history unfolded.
And God said unto Moses, I AM THAT I AM: and he said, Thus shalt thou say unto the children of Israel, I AM hath sent me unto you.