Quran 4:155 An-Nisa, ayah 155 of 176

فَبِمَا نَقْضِهِم مِّيثَـٰقَهُمْ وَكُفْرِهِم بِـَٔايَـٰتِ ٱللَّهِ وَقَتْلِهِمُ ٱلْأَنۢبِيَآءَ بِغَيْرِ حَقٍّ وَقَوْلِهِمْ قُلُوبُنَا غُلْفٌۢ ۚ بَلْ طَبَعَ ٱللَّهُ عَلَيْهَا بِكُفْرِهِمْ فَلَا يُؤْمِنُونَ إِلَّا قَلِيلًا ۝١٥٥

4:155 Then because of their breaking of their covenant, and their disbelieving in the revelations of Allah, and their slaying of the prophets wrongfully, and their saying: Our hearts are hardened - Nay, but Allah set a seal upon them for their disbelief, so that they believe not save a few -