Midrash su I Re 18:37

I will be that I will be (Ex. 3, 14).The Holy One, praised be He! said unto Moses, "Go and tell Israel that I was with you during this subjugation and I will be with you during the next subjugation." So Moses said unto Him: "Sovereign of the Universe, is not the affliction terrible enough when it is really present [without telling of it beforehand]?" Whereupon the Holy One, praised be He! said unto Moses: "Then go and tell, 'I will be,' sent me unto you." Answer me, O Lord, answer me (I Kings 18, 37). R. Abuhu said: "Why did Elijah say twice. Answer me? We infer from this that Elijah said, before the Holy One, praised be He! 'Sovereign of the Universe, answer me that a fire shall come down from Heaven and consume everything that is upon the altar; and answer me, to remove from their mind that they shall not think it was the result of sorcery,' as it is said (Ib.) Thou hast turned their hearts back again.":