ذَٰلِكَ بِأَنَّهُمْ ءَامَنُوا۟ ثُمَّ كَفَرُوا۟ فَطُبِعَ عَلَىٰ قُلُوبِهِمْ فَهُمْ لَا يَفْقَهُونَ
That is because they believed, and then they disbelieved; so their hearts were sealed over, and they do not understand.
Uthmani script · Saheeh International · Quran 63:3