﴿ ٱلَّذِينَ كَذَّبُوا۟ بِٱلْكِتَٰبِ وَبِمَآ أَرْسَلْنَا بِهِۦ رُسُلَنَا ۖ فَسَوْفَ يَعْلَمُونَ ﴾

“they who give the lie to this divine writ and [thus] to all [the messages] with which We sent forth Our apostles [of old]? But in time they will come to know [how blind they have been: they will know it on Judgment Day],”

(Those who deny the Scripture) the Qur'an (and that wherewith we send Our messengers) of Scriptures. (But they will come to know) on the Day of Judgement what will be done to them. This is a threat to them,