And those who disbelieve say: "Why is not a sign sent down to him (Muhammad SAW) from his Lord?" Say: "Verily, Allah sends astray whom He wills and guides unto Himself those who turn to Him in repentance." 27 those who believe and whose hearts find comfort in the remembrance of God -- surely in the remembrance of God hearts can find comfort. 28 (As for) those who believe and do good, a good final state shall be theirs and a goodly return. 29 And thus We have sent you among a nation before which other nations have passed away, that you might recite to them what We have revealed to you and (still) they deny the Beneficent Allah. Say: He is my Lord, there is no god but He; on Him do I rely and to Him is my 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