Those who have rejected (the message of Muhammad) say: "Why has no sign been sent down upon him from his Lord?" Tell them: "Allah lets go astray those whom He wills, and guides to Himself those who turn to Him." 27 Those who believe (in the Oneness of Allah - Islamic Monotheism), and whose hearts find rest in the remembrance of Allah, Verily, in the remembrance of Allah do hearts find rest. 28 "As for those who believe and do righteous deeds -- blissful is their end." 29 We have sent you to a nation before whom there lived many nations so that you would read to them what We have revealed to you. They still deny the existence of the Beneficent God. Say, "He is my Lord besides whom there is no other God. I trust Him and turn to Him in repentance." 30 And if there had been a Quran with which mountains could be moved (from their places), or the earth could be cloven asunder, or the dead could be made to speak (it would not have been other than this Quran). But the decision of all things is certainly with Allah. Have not then those who believe yet known that had Allah willed, He could have guided all mankind? And a disaster will not cease to strike those who disbelieve because of their (evil) deeds or it (i.e. the disaster) settle close to their homes, until the Promise of Allah comes to pass. Certainly, Allah does not fail in His Promise. 31