﴿ لَوْ يَعْلَمُ ٱلَّذِينَ كَفَرُوا۟ حِينَ لَا يَكُفُّونَ عَن وُجُوهِهِمُ ٱلنَّارَ وَلَا عَن ظُهُورِهِمْ وَلَا هُمْ يُنصَرُونَ ﴾

“If they but knew - they who are bent on deny­ing the truth - [that there will come] a time when they will not be able to ward off the fire from their faces, nor from their backs, and will not find any succour!”

Please check ayah 21:40 for complete tafsir.