13. He merges the night into the day (i.e. the decrease in the hours of the night is added to the hours of the day), and He merges the day into the night (i.e. the decrease in the hours of the day is added to the hours of the night). And He has subjected the sun and the moon: each runs its course for a term appointed. Such is Allâh, your Lord; His is the kingdom. And those, whom you invoke or call upon instead of Him, own not even a Qitmîr (the thin membrane over the date-stone).