NOW THOSE who are bent on denying the truth [of the Prophet's message] say: "Why has no miraculous sign ever been bestowed upon him from on high by his Sustainer?" Say: "Behold, God lets go astray him who wills [to go astray,] just as He guides unto Himself all who turn unto Him 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 The righteously striving believers will receive abundant blessings and the best eternal dwelling. 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 Had there been a Qur'an which could have made the mountains move, or the earth to cleave asunder, or the dead to speak, yet all authority belongs to God. Have the believers not learnt that if God had so willed He could have guided all mankind? As for unbelievers, they will be visited by misfortune endlessly for what they have done; or it would sit in their homes till the promised threat of God comes to pass. Surely God does not go back on His promise. 31