Sudden Nature of Death

قَدْ خَسِرَ ٱلَّذِينَ كَذَّبُوا۟ بِلِقَآءِ ٱللَّهِ ۖ حَتَّىٰٓ إِذَا جَآءَتْهُمُ ٱلسَّاعَةُ بَغْتَةً قَالُوا۟ يَـٰحَسْرَتَنَا عَلَىٰ مَا فَرَّطْنَا فِيهَا وَهُمْ يَحْمِلُونَ أَوْزَارَهُمْ عَلَىٰ ظُهُورِهِمْ ۚ أَلَا سَآءَ مَا يَزِرُونَ

Those will have lost who deny the meeting with Allāh, until when the Hour [of resurrection] comes upon them unexpectedly, they will say, "Oh, [how great is] our regret over what we neglected concerning it [i.e., the Hour]," while they bear their burdens [i.e., sins] on their backs. Unquestionably, evil is that which they bear.