Those who deny the truth ask, "Why has no Sign been sent down to him by his Lord?" Say, "God lets go astray those whom He wills and guides to Himself those who turn to Him, 27 Who have believed and whose hearts have rest in the remembrance of Allah. Verily in the remembrance of Allah do hearts find rest! 28 Those who believe and do the right, have happiness, and an excellent resting place. 29 Thus We have sent thee among a nation before which other nations have passed away, to recite to them that We have revealed to thee; and yet they disbelieve in the All-merciful. Say: 'He is my Lord -- there is no god but He. In Him I have put my trust, and to Him I turn.' 30 Had it been possible for a Lecture to cause the mountains to move, or the earth to be torn asunder, or the dead to speak, (this Qur'an would have done so). Nay, but Allah's is the whole command. Do not those who believe know that, had Allah willed, He could have guided all mankind? As for those who disbelieve, disaster ceaseth not to strike them because of what they do, or it dwelleth near their home until the threat of Allah come to pass. Lo! Allah faileth not to keep the tryst. 31