﴿ هَلْ يَنظُرُونَ إِلَّا ٱلسَّاعَةَ أَن تَأْتِيَهُم بَغْتَةًۭ وَهُمْ لَا يَشْعُرُونَ ﴾

“ARE THEY [who are lost in sin] but waiting for the Last Hour - [waiting] that it come upon them of a sudden, without their being aware [of its approach]?”

Are they that is the Meccan disbelievers awaiting anything that is to say — they are in fact awaiting nothing — but that Hour should come upon them an ta’tiyahum substitutes for al-sā‘ata ‘the Hour’ suddenly unexpectedly while they are unaware? of the time of its coming beforehand.