﴿ لَا يُقَٰتِلُونَكُمْ جَمِيعًا إِلَّا فِى قُرًۭى مُّحَصَّنَةٍ أَوْ مِن وَرَآءِ جُدُرٍۭ ۚ بَأْسُهُم بَيْنَهُمْ شَدِيدٌۭ ۚ تَحْسَبُهُمْ جَمِيعًۭا وَقُلُوبُهُمْ شَتَّىٰ ۚ ذَٰلِكَ بِأَنَّهُمْ قَوْمٌۭ لَّا يَعْقِلُونَ ﴾

“Never will they fight you, [even] in unison, otherwise than from within fortified strongholds or from behind walls. Severe is their warlike discord among themselves: thou wouldst think that they are united, whereas [in fact] their hearts are at odds [with one another]: this, because they are people who will not use their reason.”

(They) i.e. Banu Qurayzah and Banu'l-Nadir (will not fight against you in a body save in fortified villages or from behind walls) or if there is between you and them walls. (Their adversity among themselves is very great) He says: their fighting against each other is great, for they fought against their own folk and not against the Prophet (pbuh) and his Companions. (Ye think of them as a whole) united (whereas their hearts are diverse) whereas they differ a great deal. (That) differing and betrayal (is because they are a folk who have no sense) is because they do not understand Allah's command and divine Oneness.