﴿ أَلَمْ تَرَ إِلَىٰ رَبِّكَ كَيْفَ مَدَّ ٱلظِّلَّ وَلَوْ شَآءَ لَجَعَلَهُۥ سَاكِنًۭا ثُمَّ جَعَلْنَا ٱلشَّمْسَ عَلَيْهِ دَلِيلًۭا ﴾

“Art thou not aware of thy Sustainer [through His works]? - how He causes the shadow to lengthen [towards the night] when, had He so willed, He could indeed have made it stand still: but then, We have made the sun its guide;”

(Hast thou not seen how thy Lord hath spread the shade) after sunrise and before sunset, from the East to the West. (And if He willed He could have made it) i.e. the shade (still) with no sun, (then We have made the sun its) the shade's (pilot) wherever one finds the sun one expects to find the shade before that; it is also said that this means: a guide which comes after it;