﴿ بِسْمِ ٱللَّهِ ٱلرَّحْمَٰنِ ٱلرَّحِيمِ إِذَا وَقَعَتِ ٱلْوَاقِعَةُ ﴾

“WHEN THAT which must come to pass [at last] comes to pass,”

And from his narration on the authority of Ibn 'Abbas that he said regarding the interpretation of Allah's saying (When the event befalleth): '(When the event befalleth) He says: when the Day of Judgement comes.