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 find peace in their hearts from the contemplation of God: Surely there is peace of heart in the contemplation of God!" 28 Those who have believed and done righteous deeds - a good state is theirs and a good return. 29 Thus We have sent thee unto a community before whom other communities have passed away, in order that thou mayest recite unto them that which We have revealed unto thee; yet they disbelieve in the Compassionate. Say thou: He is my Lord, there is no god but he; on Him I rely, and unto Him is my return in penitence. 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