Surah Al-Munafiqun 63:3
ذَٰلِكَ بِأَنَّهُمْ ءَامَنُوا۟ ثُمَّ كَفَرُوا۟ فَطُبِعَ عَلَىٰ قُلُوبِهِمْ فَهُمْ لَا يَفْقَهُونَ ٣
EnglishSahih International
That is because they believed, and then they disbelieved; so their hearts were sealed over, and they do not understand.