Al-Furqan 25:62

Wahuwa allathee jaAAala allayla wannaharakhilfatan liman arada an yaththakkara aw aradashukoora

And it is He who has made the night and the day in succession for whoever desires to remember or desires gratitude.

And He is the One who made the day and the night following each other, for the one who wishes to be mindful or wishes to show gratitude.