Surah Al-Muddaththir 74:31

وَمَا جَعَلْنَآ أَصْحَـٰبَ ٱلنَّارِ إِلَّا مَلَـٰٓئِكَةً ۙ وَمَا جَعَلْنَا عِدَّتَهُمْ إِلَّا فِتْنَةً لِّلَّذِينَ كَفَرُوا۟ لِيَسْتَيْقِنَ ٱلَّذِينَ أُوتُوا۟ ٱلْكِتَـٰبَ وَيَزْدَادَ ٱلَّذِينَ ءَامَنُوٓا۟ إِيمَـٰنًا ۙ وَلَا يَرْتَابَ ٱلَّذِينَ أُوتُوا۟ ٱلْكِتَـٰبَ وَٱلْمُؤْمِنُونَ ۙ وَلِيَقُولَ ٱلَّذِينَ فِى قُلُوبِهِم مَّرَضٌ وَٱلْكَـٰفِرُونَ مَاذَآ أَرَادَ ٱللَّهُ بِهَـٰذَا مَثَلًا ۚ كَذَٰلِكَ يُضِلُّ ٱللَّهُ مَن يَشَآءُ وَيَهْدِى مَن يَشَآءُ ۚ وَمَا يَعْلَمُ جُنُودَ رَبِّكَ إِلَّا هُوَ ۚ وَمَا هِىَ إِلَّا ذِكْرَىٰ لِلْبَشَرِ

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 Allāh intend by this as an example?" Thus does Allāh 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.

Translation: Saheeh International

Tafsir

And We have appointed only angels as wardens of the Fire in other words and so they cannot be withstood as these disbelievers are wont to imagine; and We have made their number so only as a stumbling-block a cause for error for those who disbelieve when they then say ‘Why are there nineteen of them?’ so that those who …

Excerpt from Tafsir al-Jalalayn, commentary on 74:31, via Quran.com. The reader has the full commentary and 9 more tafsirs.