Surah Al Muddaththir Ayat 31

We have appointed only angels to be wardens of the Fire, and caused their number to be a stumbling block for those who disbelieve; so that those given the Scripture may attain certainty; and those who believe may increase in faith; and those given the Scripture and the believers may not doubt; and those in whose hearts is sickness and the unbelievers may say, “What did God intend by this parable?” Thus God leads astray whom He wills, and guides whom He wills. None knows the soldiers of your Lord except He. This is nothing but a reminder for the mortals.