﴿ وَيَحْلِفُونَ بِٱللَّهِ إِنَّهُمْ لَمِنكُمْ وَمَا هُم مِّنكُمْ وَلَٰكِنَّهُمْ قَوْمٌۭ يَفْرَقُونَ ﴾

“And they swear by God that they do indeed belong to you -the while they do not belong to you, but are [only] people ridden by fear:”

And they swear by God that they truly are of you that is that they are believers; but they are not of you; they are a folk who are afraid that you should deal with them as you have done with the idolaters and so they swear merely in pretence in order to protect themselves.