Where is the decisive revelation of the name of Israel's tribal deity? Mount Sinai:
12 [The Angel of the LORD] said, "But I WILL BE with you, and this shall be the sign for you, that I have sent you: when you have brought the people out of Egypt, you shall serve God on this mountain." 13 Then Moses said to God, "If I come to the people of Israel and say to them, 'The God of your fathers has sent me to you,' and they ask me, 'What is His name?' what shall I say to them?" 14 God said to Moses, "I WILL BE WHO I WILL BE". And He said, "Say this to the people of Israel, "I WILL BE" has sent me to you.'" 15 God also said to Moses, "Say this to the people of Israel, 'The LORD, the God of your fathers, the God of Abraham, the God of Isaac, and the God of Jacob, has sent me to you.' This is my name forever, and thus I am to be remembered throughout all generations. (Exodus 3:12-15)
1. The name Yahweh is taken by many scholars to be the nominal form of the first person verb "I WILL BE". (i.e. Yahweh is what we call Him, "I WILL BE WHO I WILL BE" is what He says about Himself). Thus the burning bush represents His own unpacking of the name of Yahweh.
2. This unpacking of His own name is not His handing over to us of some interpretive maxim by which we can understand Him. Emphatically it is the LORD holding onto His own prerogative to self-disclose. The possibility for knowing the LORD is not delivered over to man - He holds onto it forever. He will always be the One to intepret Himself. We must continually come to Him for knowledge of Him.
3. The future tense is probably the better translation of what's usually rendered "I AM" - it's exactly the same Hebrew as v12 "I will be with you..." It's therefore not a static thing. It's not basically the claim to be self-existent, it's something much more dynamic.
4. It's ironic that people use the 'I AM' as itself a proof-text for presupposing their own classical attributes of God (like His aseity or whatever). The whole point of this name is that He defines who He is in contrast to every human definition - even (and especially!) the most philosophically sophisticated. "I will be Who I will be - not who you say I am."
5. We must never forget the context of His self-identification - decisive historical action. Involvement. Redemption. Exodus. He will be who He will be in salvation. He drops His name into conversation first in verse 12 and it's in the form of a promise: "I will be with you." And He follows verse 14 with the reassurance that He, the LORD, is the God of your fathers - the tribal deity of Israel.
All in all, Yahweh's declaration that He is the great I AM is not the same as Him claiming to be Unoriginate. For some the "I AM" is equivalent to some divine attribute of self-existence, as though it's the Hebrew form of "I am the Ground of all Being." It is not as though the philosopher who has thought of the unmoved Mover has thought of Yahweh. Not at all. The I AM is met only as the Redeemer of His particular people. He is met in the context of promise, in the context of covenant. He is met as the tribal deity of Israel - in this way He proves His unassailable right to define Himself.