The Unbelievers say: "Why is not a sign sent down to him from his Lord?" Say: "Truly Allah leaveth, to stray, whom He will; But He guideth to Himself those who turn to Him in penitence,- 27 They are those who believe and whose hearts find rest in the remembrance of Allah. Lo! in the remembrance of Allah hearts do find rest. 28 For those who believe and do good works is blessedness and blessed resort' 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 And what would have happened were a Qur'an to be revealed wherewith mountains could be set in motion, or the earth cleft, or the dead made to speak? (To show such signs is not at all difficult for) everything rests entirely with Allah. So, do not the people of faith (still look forward to such a sign in response to the demand of the unbelievers and) despair as a result of knowing that had Allah so willed, He could have guided all to the Truth. Misfortune continues to afflict the unbelievers on account of their misdeeds, or to befall on locations close to their habitation. This will continue until Allah's promise (of chastisement) is fulfilled. Indeed Allah does not go back upon His promise. 31