المنٰفقون — Al-Munafiqun Ayat 3

ذٰلِكَ بِاَنَّهُمْ اٰمَنُوْا ثُمَّ كَفَرُوْا فَطُبِعَ عَلٰى قُلُوْبِهِمْ فَهُمْ لَا يَفْقَهُوْنَ

Żālika bi'annahum āmanū ṡumma kafarū faṭubi‘a ‘alā qulūbihim fahum lā yafqahūn(a).

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