۞ 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 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 replied: “Allah alone knows about this. I only convey to you the Message that I have been sent with. But I see that you are an ignorant people.” 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 yet, We had established them securely in a manner in which We have never established you, [O people of later times;] and We had endowed them with hearing, and sight, and [knowledgeable] hearts: but neither their hearing, nor their sight, nor their hearts were of the least avail to them, seeing that they went on rejecting God's messages; and [in the end] they were overwhelmed by the very thing which they had been wont to deride. 26