فَبِمَا نَقْضِهِمْ مِّيْثَاقَهُمْ وَكُفْرِهِمْ بِاٰيٰتِ اللّٰهِ وَقَتْلِهِمُ الْاَنْۢبِيَاۤءَ بِغَيْرِ حَقٍّ وَّقَوْلِهِمْ قُلُوْبُنَا غُلْفٌ ۗ بَلْ طَبَعَ اللّٰهُ عَلَيْهَا بِكُفْرِهِمْ فَلَا يُؤْمِنُوْنَ اِلَّا قَلِيْلًاۖ ( النساء: ١٥٥ )
Fabimaa naqdihim meesaaqahum wa kufrihim bi Aayaatil laahi wa qatlihimul Ambiyaaa'a bighairi haqqinw wa qawlihim quloobunna ghulf; bal taba'al laahu 'alaihaa bikufrihim falaa yu'minoona illaa qaleelaa (an-Nisāʾ 4:155)
Sahih International:
And [We cursed them] for their breaking of the covenant and their disbelief in the signs of Allah and their killing of the prophets without right and their saying, "Our hearts are wrapped" [i.e., sealed against reception]. Rather, Allah has sealed them because of their disbelief, so they believe not, except for a few. (An-Nisa [4] : 155)
1 Mufti Taqi Usmani
So, (they met their fate) for breaking their pledge, and for their disbelief in the verses of Allah, and for their slaying of the prophets unjustly, and for their saying, “Our hearts are sealed” - rather, Allah has set a seal over them for their disbelief, so they do not believe but a little