But if you do (it) not and never shall you do (it), then be on your guard against the fire of which men and stones are the fuel; it is prepared for the unbelievers.

And guard yourselves against the fire which has been prepared for the unbelievers.

And We have not made the wardens of the fire others than angels, and We have not made their number but as a trial for those who disbelieve, that those who have been given the book may be certain and those who believe may increase in faith, and those who have been given the book and the believers may not doubt, and that those in whose hearts is a disease and the unbelievers may say: What does Allah mean by this parable? Thus does Allah make err whom He pleases, and He guides whom He pleases, and none knows the hosts of your Lord but He Himself; and this is naught but a reminder to the mortals.