﴿ إِلَٰهُكُمْ إِلَٰهٌۭ وَٰحِدٌۭ ۚ فَٱلَّذِينَ لَا يُؤْمِنُونَ بِٱلْءَاخِرَةِ قُلُوبُهُم مُّنكِرَةٌۭ وَهُم مُّسْتَكْبِرُونَ ﴾

“Your God is the One God: but because of their false pride, the hearts of those who do not believe in the life to come refuse to admit this [truth].”

Please check ayah 16:23 for complete tafsir.