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 God -- surely in the remembrance of God hearts can find comfort. 28 The righteously striving believers will receive abundant blessings and the best eternal dwelling. 29 Thus have We raised thee [O Muhammad] as Our Apostle amidst a community [of unbelievers] before whose time [similar] communities have come and gone, so that thou might propound to them what We have revealed unto thee: for [in their ignorance] they deny the Most Gracious! Say: "He is my Sustainer. There is no deity save Him. In Him have I placed my trust, and unto Him is my recourse!" 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