Rabbi Jannai said: || All the hosts of heaven pass away and are renewed every day. What are the hosts of heaven? The sun, the moon, the stars, and the constellations. Know that it is so.
Come and see, for when the sun turns in order to set in the west, it bathes in the waters of the Ocean and extinguishes the flames of the sun, and no light is left, and it has no flame all night long until it comes to the east. When it arrives at the east it washes itself in the river of fire, like a man who kindles his lamp in the midst of the fire. Likewise the sun kindles its lamps and puts on its flames and ascends to give light upon the earth, and it renews every day the work of the Creation.
And thus (it is) until even comes. At evening-time the moon and the stars and the constellations wash themselves in the river of hail, and they ascend to give light upon the earth. In the future that is to come, the Holy One, blessed be He, will renew them and add to their light a sevenfold light, as it is said, "Moreover, the light of the moon shall be as the light of the sun, and the light of the sun shall be sevenfold, as the light of seven days" (Isa. 30:26).
"In the day" (ibid.). Like which day? In the day of the redemption of Israel, as it is said, "In the day that the Lord bindeth up the hurt of his people" (ibid.).