The nature of hellfire

فَأَمَّا ٱلَّذِينَ شَقُوا۟ فَفِى ٱلنَّارِ لَهُمْ فِيهَا زَفِيرٌ وَشَهِيقٌ

As for those who were [destined to be] wretched, they will be in the Fire. For them therein is [violent] exhaling and inhaling.

لَّا بَارِدٍ وَلَا كَرِيمٍ

Neither cool nor beneficial.

لَا يَصْلَىٰهَآ إِلَّا ٱلْأَشْقَى

None will [enter to] burn therein except the most wretched one