۞ 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: “Have you come to us to turn us away from our gods? Then, bring upon us the scourge that you threaten us with. Do so if you are truthful.” 22 Said he: "Knowledge [of when it is to befall you] rests with God alone: I but convey unto you the message with which I have been entrusted; but I see that you are people ignorant [of right and wrong]!" 23 So when they saw it as a cloud advancing towards their valleys, they said: "This is just a passing cloud that will bring us rain." "No. It is what you were trying to hasten: The wind which carries the grievous punishment! 24 bound to destroy everything at its Sustainer's behest!" And then they were so utterly wiped out that nothing could be seen save their [empty] dwellings: thus do We requite people lost in sin. 25 And We had established them in that which We have not established you, and We made for them hearing, sight, and hearts, but their hearing, sight, and hearts did not help them a thing, because they disbelieved the signs of Allah. And what they mocked encompassed them. 26