Say: I exhort you only to one thing, that rise up for Allah's sake in twos and singly, then ponder: there is no madness in your fellow-citizen; he is only a warner to you before a severe chastisement.

And mention the brother of Ad; when he warned his people in the sandy plains,-- and indeed warners came before him and after him-- saying Serve none but Allah; surely I fear for you the punishment of a grievous day.