﴿ يَٰٓأَيُّهَا ٱلَّذِينَ ءَامَنُوا۟ قُوٓا۟ أَنفُسَكُمْ وَأَهْلِيكُمْ نَارًۭا وَقُودُهَا ٱلنَّاسُ وَٱلْحِجَارَةُ عَلَيْهَا مَلَٰٓئِكَةٌ غِلَاظٌۭ شِدَادٌۭ لَّا يَعْصُونَ ٱللَّهَ مَآ أَمَرَهُمْ وَيَفْعَلُونَ مَا يُؤْمَرُونَ ﴾

“O YOU who have attained to faith! Ward off from yourselves and those who are close to you that fire [of the hereafter] whose fuel is human beings and stones: [lording] over it are angelic powers awesome [and] severe, who do not disobey God in whatever He has commanded them, but [always] do what they are bidden to do.”

O you who believe! Guard yourselves and your families by enjoining obedience to God against a Fire whose fuel is disbelieving people and stones such as those idols of theirs made of that stone — the meaning is that it is extremely hot fuelled by the above-mentioned unlike the fire of this world which is fuelled by wood and the like — over which stand angels its keepers — numbering nineteen as will be stated in sūrat al-Muddaththir Q. 7430 — stern a sternness of the heart mighty in their power of assault who do not disobey God in what He commands them mā amarahum is a substitution for His Majesty ‘God’ in other words they do not disobey the command of God but do what they are commanded — this is reiterated for emphasis; the verse is meant as a threat to deter believers from apostatising and for hypocrites who believe only with their tongues and not with their hearts.