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 one of His signs is the creation of the heavens and the earth and what He has spread forth in both of them of living beings; and when He pleases He is all-powerful to gather them together.