۞ 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, 'Knowledge is only with God, and I deliver to you the Message with which I was sent; but I see you are an ignorant people.' 23 When they saw the scourge advancing towards their valleys, they said: “This is a cloud that will bring much rain to us.” “By no means; it is what you had sought to hasten -- a wind-storm bearing a grievous chastisement 24 It will destroy everything at the bidding of its Lord." So in the morning there was nothing but their empty dwellings to be seen. That is how We requite the sinners. 25 And assuredly We had established them in that flourishing condition wherein We have not established you, and We had appointed for them hearing and sight and hearts; yet their hearing and sight and heart availed them not at all, they became wont to gainsay the revelations of Allah, and surrounded them that whereat they had been mocking. 26