Why Israel Counts by the Moon and Esau by the Sun

"This month shall be for you" (Exodus 12:2): you count by it, and the nations of the world do not count by it. Rabbi Levi in the name of Rabbi Yose bar Le'ai said: it is the way of the world that the great reckons by the great and the small by the small. Esau, who is great, reckons by the sun, which is great; and Jacob, who is small, reckons by the moon, which is small. Rabbi Nachman said: and this is a good sign. Just as the great one rules by day and does not rule by night, so the wicked Esau rules in this world and does not rule in the world to come. Just as the small one rules by day and by night, so Jacob rules in this world and in the world to come. Rabbi Nachman said: so long as the light of the great one shines in the world, the light of the small one is not noticed; once the light of the great one sets, the light of the small one becomes known. So long as the light of the wicked Esau shines in the world, the light of Jacob is not noticed; once the light of the wicked Esau sets, the light of Jacob becomes known, "Arise, shine, for your light has come" (Isaiah 60:1). Rabbi Shimon ben Yochai taught: in three matters Moses had difficulty, and the Holy One, blessed be He, showed him as if with a finger: the menorah, the creeping things, and the new moon. The menorah, "And this is the work of the menorah" (Numbers 8:4). The creeping things, "And these are unclean for you" (Leviticus 11:29). The new moon, "This month shall be for you" (Exodus 12:2).