Surah At-Tawbah 9:56

وَيَحْلِفُونَ بِٱللَّهِ إِنَّهُمْ لَمِنكُمْ وَمَا هُم مِّنكُمْ وَلَـٰكِنَّهُمْ قَوْمٌ يَفْرَقُونَ

And they swear by Allāh that they are from among you while they are not from among you; but they are a people who are afraid.

Translation: Saheeh International

Tafsir

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.

Excerpt from Tafsir al-Jalalayn, commentary on 9:56, via Quran.com. The reader has the full commentary and 9 more tafsirs.