And those who disbelieved say, "Why has a sign not been sent down to him from his Lord?" Say, [O Muhammad], "Indeed, Allah leaves astray whom He wills and guides to Himself whoever turns back [to Him] - 27 those who believe, and whose hearts find their rest in the remembrance of God - for, verily, in the remembrance of God [men's] hearts do find their rest: 28 "For those who believe and work righteousness, is (every) blessedness, and a beautiful place of (final) return." 29 As such, We have sent you forth to a nation before whom others have passed away in order that you recite to them what We have revealed to you. Yet they disbelieve the Merciful. Say: 'He is my Lord. There is no god except He. In Him I have put my trust, and to Him 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