The Cow - 2:189 They ask you about the phases of the moon. Say that it is a measure of time for mankind and for the pilgrimage. Goodness is not beating around the bush, goodness is abstinence. Be honest. Listen to Allah for your salvation.
What are the phases of the moon?
Prophet Jonah/10:5 He made the sun a source of light and the moon a light. He has given it phases so that you may know the number of years and reckoning. Allah has created these only for a truth. This is how He explains the verses to a people who know.

Yaseen/36:39 And We appointed for the moon various stages until it turns into a dry palm branch.