Quran Al-Munafiqun 63:3

ذَٰلِكَ بِأَنَّهُمۡ ءَامَنُواْ ثُمَّ كَفَرُواْ فَطُبِعَ عَلَىٰ قُلُوبِهِمۡ فَهُمۡ لَا يَفۡقَهُونَ

Translation

That is because they believed, and then they disbelieved; so their hearts were sealed over, and they do not understand.