۞ And make mention (O Muhammad) of the brother of A'ad when he warned his folk among the wind-curved sandhills - and verily warners came and went before and after him - saying: Serve none but Allah. Lo! I fear for you the doom of a tremendous Day. 21 They answered: "Hast thou come to seduce us away from our gods? Bring, then, upon us that [doom] with which thou threaten us, if thou art a man of truth!" 22 He said: "The Knowledge (of when it will come) is only with Allah: I proclaim to you the mission on which I have been sent: But I see that ye are a people in ignorance!".. 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 It shall annihilate everything by the command of its Lord. Wherefore they became such that naught could be seen save their dwellings Thus We requite a nation of the culprits. 25 And We had established them in that wherein We have not established you, and We appointed for them hearing, and sight, and hearts; and yet their hearing, their sight and their hearts availed them nothing, since they denied the signs of God, and they were encompassed by that they mocked at. 26