Hypocrisy, grudges
وَمِمَّنْ حَوْلَكُمْ مِنَ الْأَعْرَابِ مُنَافِقُونَ ۖ وَمِنْ أَهْلِ الْمَدِينَةِ ۖ مَرَدُوا عَلَى النِّفَاقِ لَا تَعْلَمُهُمْ ۖ نَحْنُ نَعْلَمُهُمْ ۚ سَنُعَذِّبُهُمْ مَرَّتَيْنِ ثُمَّ يُرَدُّونَ إِلَىٰ عَذَابٍ عَظِيمٍ {101}
And from the ones around you from the Bedouins are hypocrites, and from the people of Al-Medina are stubborn upon ‘النِّفَاقِ’ the hypocrisy. You do not know them, We Know them. We will be Punishing them twice, then they will be Returned to the grievous Punishment [9:101]