Warning and threat (wa'id)

فَإِن لَّمْ تَفْعَلُوا۟ وَلَن تَفْعَلُوا۟ فَٱتَّقُوا۟ ٱلنَّارَ ٱلَّتِى وَقُودُهَا ٱلنَّاسُ وَٱلْحِجَارَةُ ۖ أُعِدَّتْ لِلْكَـٰفِرِينَ

But if you do not - and you will never be able to - then fear the Fire, whose fuel is people and stones, prepared for the disbelievers.