And the disbelievers said, “Why was not a sign sent down upon him from his Lord?” Proclaim, “Indeed Allah sends astray whomever He wills, and guides towards Himself the one who comes towards Him.” 27 Those who believe, their hearts being at rest in God's remembrance -- in God's remembrance are at rest the hearts 28 Those who believe and do the right, have happiness, and an excellent resting place. 29 Thus We have sent you to a people, before whom other peoples have passed away, so that you may recite to them what We have revealed to you. Yet they deny the Gracious God. Say, "He is my Lord; there is no god but He. In Him I put my trust and to Him I shall return." 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