There's a verse in Exodus, 3:14, I think, in which God tells Moses, "I AM THAT I AM" (caps in KJV). This is surely what Jesus is referring to, but very few poeple seem to know that "I AM" was an Egyptian deity, called by them "Nuk Pu Nuk", which means "I Am Who I Am".
You can google it, or wait a bit and I'll see if I can find a link.
© Charles N. Pope, US Library of Congress. All rights reserved.