And We have set none but angels as keepers of the Fire; and We have fixed their number only as a trial for the Rejecters, in order that the People of the Book may arrive at certainty, and the Believers may increase in Faith, and so that no doubt may be left for the People of the Book and the Believers, and that those in whose hearts is a disease and the Rejecters may say, “What does Allāh intend by this?” Thus does Allāh leave to stray whom He pleases, and guide whom He pleases. And none knows the armies of your Lord except He. And this is none but a Reminder to Mankind.