He took the wood and placed it upon the back of his son Isaac, and he took the fire and the knife in his hand, and they went both of them together. Isaac said to his father: O my father! Behold the fire and the wood, where is the lamb for the burnt offering? He replied to him: My son! Thou art the lamb for the burnt offering, as it is said, "And Abraham said, God will provide for himself the lamb" (Gen. 22:8).
Rabbi Simeon said: The Holy One, blessed be He, pointed out the altar with a finger to Abraham our father, and said to him: This is the altar. That was the altar whereon Cain and Abel sacrificed; it was the same altar whereon Noah and his sons sacrificed, as it is said, "And Abraham built the altar there" (Gen. 22:9). "And Abraham built an altar there" is not written here, but "And Abraham built the altar there." That was the altar whereon the first ones (of old) had sacrificed.