The unbelievers say, 'Why has a sign not been sent down upon him from his Lord?' Say: 'God leads astray whomsoever He will, and He guides to Him all who are penitent.' 27 Those who have believed and whose hearts are assured by the remembrance of Allah. Unquestionably, by the remembrance of Allah hearts are assured." 28 For those who believe and do good works is blessedness and blessed resort' 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 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