۞ 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: Hast come to turn us away from our gods? Then bring upon us that wherewith thou threatenest us, if thou art of the truthful. 22 He said, "Knowledge [of its time] is only with Allah, and I convey to you that with which I was sent; but I see you [to be] a people behaving ignorantly." 23 So, when they saw it in the shape of a dense cloud approaching their valleys, they exclaimed, "This is only a heavy cloud which will bring us [welcome] rain!" [But Hud said]: "By no means! It is the very thing which you sought to hasten -- a wind bearing grievous suffering 24 which will destroy everything at its Lord's behest!" And in the morning there was nothing left to be seen save their [empty] dwellings: thus We repay the evil-doers. 25 We had established them firmly in a manner We have not established you. We had given them ears and eyes and hearts. But nothing availed them -- neither their ears, nor their eyes, nor their hearts, for they denied the Signs of Allah. Then what they had mocked at encompassed them. 26