Quran 74:30 - 74:31
Over it are nineteen [angels].
And We have not made the keepers of the Fire except angels. And We have not made their number except as a trial for those who disbelieve – that those who were given the Scripture will be convinced and those who have believed will increase in faith and those who were given the Scripture and the believers will not doubt and that those in whose hearts is disease [i.e., hypocrisy] and the disbelievers will say, “What does Allah intend by this as an example?” Thus does Allah send astray whom He wills and guide whom He wills. And none knows the soldiers of your Lord except Him. And it [i.e., mention of the Fire] is not but a reminder to humanity.
— Saheeh International
