وَمَا جَعَلْنَا أَصْحَابَ النَّارِ إِلَّا مَلَائِكَةً ۙ وَمَا جَعَلْنَا عِدَّتَهُمْ إِلَّا فِتْنَةً لِلَّذِينَ كَفَرُوا لِيَسْتَيْقِنَ الَّذِينَ أُوتُوا الْكِتَابَ وَيَزْدَادَ الَّذِينَ آمَنُوا إِيمَانًا ۙ وَلَا يَرْتَابَ الَّذِينَ أُوتُوا الْكِتَابَ وَالْمُؤْمِنُونَ ۙ وَلِيَقُولَ الَّذِينَ فِي قُلُوبِهِمْ مَرَضٌ وَالْكَافِرُونَ مَاذَا أَرَادَ اللَّهُ بِهَٰذَا مَثَلًا ۚ كَذَٰلِكَ يُضِلُّ اللَّهُ مَنْ يَشَاءُ وَيَهْدِي مَنْ يَشَاءُ ۚ وَمَا يَعْلَمُ جُنُودَ رَبِّكَ إِلَّا هُوَ ۚ وَمَا هِيَ إِلَّا ذِكْرَىٰ لِلْبَشَرِ (۳۱)

We appointed angels to be guardians of Hell, and we assigned their number (19) (1) to disturb the disbelievers, (2) to convince the Christians and Jews (that this is a divine scripture), (3) to strengthen the faith of the faithful, (4) to remove all traces of doubt from the hearts of Christians, Jews, as well as the believers, and (5) to expose those who harbor doubt in their hearts, and the disbelievers; they will say, "What did GOD mean by this allegory?" GOD thus sends astray whomever He wills, and guides whomever He wills. None knows the soldiers of your Lord except He. This is a reminder for the people.