Surah At-Tawbah (9:56)

وَيَحْلِفُونَ بِٱللَّهِ إِنَّهُمْ لَمِنكُمْ وَمَا هُم مِّنكُمْ وَلَٰكِنَّهُمْ قَوْمٌ يَفْرَقُونَ

And they swear by Allah that they are indeed from you, while they are not from you; rather, they are a people who are filled with fear.