۞ 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, "God alone knows when it will come, and I deliver to you the message with which I am sent, but I see you are a people who are ignorant." 23 So when they saw it as a cloud appearing in the sky advancing towards their valleys, they said: This is a cloud which will give us rain. Nay! it is what you sought to hasten on, a blast of wind in which is a painful punishment, 24 Destroying everything by the Command of its Lord! So they became such that nothing could be seen except their dwellings! Thus do We recompense the people who are Mujrimun (polytheists, disbelievers, sinners, etc.)! 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