أَفَأَمِنُوٓا۟ أَن تَأْتِيَهُمْ غَـٰشِيَةٌ مِّنْ عَذَابِ ٱللَّهِ أَوْ تَأْتِيَهُمُ ٱلسَّاعَةُ بَغْتَةً وَهُمْ لَا يَشْعُرُونَ Qur’an Yusuf (12:107)Afaaminoo an tatiyahum gh a shiyatun min AAa tha bi All a hi aw tatiyahumu a l ss a AAatu baghtatan wahum l a yashAAuroon a
Gashiyat=covering veil, pall; used for the Judgment to come, which will be so dark and appalling as to hide up all other and petty things, and be the one great reality for the souls that were slaves to evil.
The metaphor is changed, from intensity of darkness to suddenness of time. It will come before they are aware of it. Let them not feel any sense of safety in sin.