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 Those who believe, their hearts being at rest in God's remembrance -- in God's remembrance are at rest the hearts 28 So those who believe (in the message of the Truth) and do good are destined for happiness and a blissful end. 29 Thus have we sent thee amongst a People before whom (long since) have (other) Peoples (gone and) passed away; in order that thou mightest rehearse unto them what We send down unto thee by inspiration; yet do they reject (Him), the Most Gracious! Say: "He is my Lord! There is no god but He! On Him is my trust, and to Him do I turn!" 30 And if there was any qur'an by which the mountains would be removed or the earth would be broken apart or the dead would be made to speak, [it would be this Qur'an], but to Allah belongs the affair entirely. Then have those who believed not accepted that had Allah willed, He would have guided the people, all of them? And those who disbelieve do not cease to be struck, for what they have done, by calamity - or it will descend near their home - until there comes the promise of Allah. Indeed, Allah does not fail in [His] promise. 31