The Sandhills - 46:21
"Remember when Ad´s brother warned his people in the sand dunes. Before and after that he said: "Do not serve none but Allah. I fear for you the torment of a great day"."
Ad's brother:
The Heights/7:65
"And We sent to the people of Ad their brother Hud, saying: "My people, worship Allah. You have no god but Him. Will you not be righteous?"