"And it is not" - meaning the Quran - "except a reminder to the worlds," through which they are reminded of the Hereafter, Paradise, and Hellfire.
﴿وَمَا هُوَ﴾ يَعْنِي: الْقُرْآنَ ﴿إِلا ذِكْرٌ لِلْعَالَمِينَ﴾ يَذْكُرُونَ بِهِ الْآخِرَةَ وَالْجَنَّةَ وَالنَّارَ.