"Whoever turns away from it"—meaning: from the Quran and does not believe in it—"shall bear on the Day of Resurrection a burden"—meaning: a weight; referring to: sin.
﴿من أعرض عَنهُ﴾ عَنِ الْقُرْآنِ لَمْ يُؤْمِنْ بِهِ ﴿فَإِنَّهُ يَحْمِلُ يَوْمَ الْقِيَامَةِ وِزْرًا﴾ ثقلا؛ يَعْنِي: الْإِثْم