﴿ أَعَدَّ ٱللَّهُ لَهُمْ عَذَابًۭا شَدِيدًۭا ۖ فَٱتَّقُوا۟ ٱللَّهَ يَٰٓأُو۟لِى ٱلْأَلْبَٰبِ ٱلَّذِينَ ءَامَنُوا۟ ۚ قَدْ أَنزَلَ ٱللَّهُ إِلَيْكُمْ ذِكْرًۭا ﴾

“[the while] God has readied for them [yet more] suffering severe [in the life to come] Hence, remain conscious of God, O you who are endowed with insight - [you] who have attained to faith! God has indeed bestowed on you a reminder from on high:”

God has prepared for them a severe chastisement the reiteration of the threat is for emphasis. So fear God O people of pith O possessors of intellect you who believe! this is a description of the vocative or an explication of it God has certainly revealed to you a source of remembrance that is the Qur’ān;