Midrasz do Hioba 38:19

All the constellations serve the Molad of the moon and also the generations of the children of men; upon them the world stands, and everyone who is wise and understands, he understands the Molad of the moon and the generations of the children of men, and concerning them the text says, "And let them be for signs, and for seasons" (Gen. 1:14). The signs of the hours shall not depart from serving the sun by day and the moon by night.