Those who have rejected (the message of Muhammad) say: "Why has no sign been sent down upon him from his Lord?" Tell them: "Allah lets go astray those whom He wills, and guides to Himself those who turn to Him." 27 They are those who believe and whose hearts find rest in the remembrance of Allah. Lo! in the remembrance of Allah hearts do find rest. 28 For those who believe and do good works is blessedness and blessed resort' 29 Thus We send thee (O Muhammad) unto a nation, before whom other nations have passed away, that thou mayst recite unto them that which We have inspired in thee, while they are disbelievers in the Beneficent. Say: He is my Lord; there is no Allah save Him. In Him do I put my trust and unto Him is my recourse. 30 And even if there were a Quran with which the mountains were made to pass away, or the earth were travelled over with it, or the dead were made to speak thereby; nay! the commandment is wholly Allah's, Have not yet those who believe known that if Allah please He would certainly guide all the people? And (as for) those who disbelieve, there will not cease to afflict them because of what they do a repelling calamity, or it will alight close by their abodes, until the promise of Allah comes about; surely Allah will not fail in (His) promise. 31