﴿ ثُمَّ مَآ أَدْرَىٰكَ مَا يَوْمُ ٱلدِّينِ ﴾

“And once again: What could make thee conceive what that Judgment Day will be?”

(what the Day of Judgement is!) what the Day of Reckoning is. He said this to arouse his astonishment, in order to magnify such a Day.