﴿ أَفَأَمِنُوٓا۟ أَن تَأْتِيَهُمْ غَٰشِيَةٌۭ مِّنْ عَذَابِ ٱللَّهِ أَوْ تَأْتِيَهُمُ ٱلسَّاعَةُ بَغْتَةًۭ وَهُمْ لَا يَشْعُرُونَ ﴾

“Do they, then, feel free from the fear that there might fall upon them the overwhelming terror of God's chastisement, or that the Last Hour might come upon them of a sudden, without their being aware [of its approach]?”

(Deem they) i.e. the people of Mecca (themselves secure from the coming on them of a pall of Allah's punishment) such as the punishment they were exposed to on the Day of Badr, (or the coming of the Hour) or that the punishment of the Hour seizes them (suddenly while they are unaware) of the descent of punishment?