Hypocrisy (Nifaq) and the condemnation of hypocrites

وَيَقُولُونَ ءَامَنَّا بِٱللَّهِ وَبِٱلرَّسُولِ وَأَطَعْنَا ثُمَّ يَتَوَلَّىٰ فَرِيقٌ مِّنْهُم مِّنۢ بَعْدِ ذَٰلِكَ ۚ وَمَآ أُو۟لَـٰٓئِكَ بِٱلْمُؤْمِنِينَ

But they [i.e., the hypocrites] say, "We have believed in Allāh and in the Messenger, and we obey"; then a party of them turns away after that. And those are not believers.