۞ And remember the brother of Ad, when he warned his people beside the sand-dunes -- and already warners had passed away alike before him and behind him -- saying, 'Serve none but God! Truly I fear for you the chastisement of a dreadful day. 21 They said: art thou come unto us that thou mayest turn us aside from our gods? then bring thou upon us that wherewith thou threatenest us, if thou art of the truth-tellers. 22 He said: "Only God has the knowledge. I only convey to you what I have been sent with. But I see you are a foolish people." 23 Then, when they saw the (Penalty in the shape of) a cloud traversing the sky, coming to meet their valleys, they said, "This cloud will give us rain!" "Nay, it is the (Calamity) ye were asking to be hastened!- A wind wherein is a Grievous Penalty! 24 Destroying all things by commandment of its Lord. And morning found them so that naught could be seen save their dwellings. Thus do We reward the guilty folk. 25 And verily We had empowered them with that wherewith We have not empowered you, and had assigned them ears and eyes and hearts; but their ears and eyes and hearts availed them naught since they denied the revelations of Allah; and what they used to mock befell them. 26