And the moon - We have determined for it phases, until it returns [appearing] like the old date stalk.
It is not allowable for the sun to reach the moon, nor does the night overtake the day, but each, in an orbit, is swimming. (36:39-40)
The verses are saying the moon has a path and the shadows on moons indicates the paths of sun and moon are different, and sun have different path , night/day refers to the relation of sun and earth with all three entities having different paths.
