And if their turning away is hard on you, then if you can seek an opening (to go down) into the earth or a ladder (to ascend up) to heaven so that you should bring them a sign and if Allah had pleased He would certainly have gathered them all on guidance, therefore be not of the ignorant.

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.