فَكَذَّبُوهُ فَأَخَذَهُمْ عَذَابُ يَوْمِ ٱلظُّلَّةِ ۚ إِنَّهُۥ كَانَ عَذَابَ يَوْمٍ عَظِيمٍ

Fakaththaboohu faakhathahumAAathabu yawmi aththullati innahu kanaAAathaba yawmin AAatheem

And they denied him, so the punishment of the day of the black cloud seized them. Indeed, it was the punishment of a terrible day.