Midrasch zu Jeschijahu 8:22

THE CREATION ON THE SECOND DAY
ON the second day the Holy One, blessed be He, created the firmament, the angels, fire for flesh and blood, and the fire of Gehinnom. Were not heaven and earth created on the first day, as it is said, "In the beginning God created the heaven and the earth" (Gen. 1:1)? Which firmament was created on the second day? Rabbi Eliezer said: || It was the firmament which is above the heads of the four Chajjôth (living creatures), (as it is said), "And over the head of the Chajjôth there was the likeness of a firmament, like the colour of the terrible crystal" (Ezek. 1:22). What is the meaning of (the expression), "like the colour of the terrible crystal"? It means like precious stones and pearls; it illuminates all the heavens like a lamp which is illuminating the whole house and like the sun which is shining with maximum intensity at noonday, as it is said, "The light dwelleth with him" (Dan. 2:22); and like this in the future will the righteous shed light, as it is said, "And they that be wise shall shine as the brightness of the firmament" (Dan. 12:3). Were it not for that firmament the world would be engulfed by the waters above it and below it; but (the firmament) divides the waters (above) from the waters (below), as it is said, "And God said, Let there be a firmament in the midst of the waters, (and let it divide the waters from the waters)" (Gen. 1:6), it illuminates between the waters above and the waters below.