Those who disbelieve say: If only a portent were sent down upon him from his Lord! Say: Lo! Allah sendeth whom He will astray, and guideth unto Himself all who turn (unto Him), 27 those who believe, and whose hearts find comfort in the remembrance of Allah. Is it not with the remembrance of Allah that hearts are satisfied. 28 The righteously striving believers will receive abundant blessings and the best eternal dwelling. 29 We have sent you to a nation before whom there lived many nations so that you would read to them what We have revealed to you. They still deny the existence of the Beneficent God. Say, "He is my Lord besides whom there is no other God. I trust Him and turn to Him in repentance." 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