Surah Al-Hashr (The Banishment), Verse 14

لَا یُقَاتِلُوْنَكُمْ جَمِیْعًا اِلَّا فِیْ قُرًی مُّحَصَّنَةٍ اَوْ مِنْ وَّرَآءِ جُدُرٍ بَاْسُهُمْ بَیْنَهُمْ شَدِیْدٌ تَحْسَبُهُمْ جَمِیْعًا وَّقُلُوْبُهُمْ شَتّٰی ذٰلِكَ بِاَنَّهُمْ قَوْمٌ لَّا یَعْقِلُوْنَ ۟

Laa yuqaatiloonakum jamee'an illaa fee quram muhas sanatin aw minw waraaa'i judur; baasuhum bainahum shadeed; tahsabuhum jamee'anw-wa quloobuhum shatta; zaalika biannahum qawmul laa ya'qiloon

“They will not fight you (even) together, except in fortified townships, or from behind walls. Strong is their fighting (spirit) amongst themselves: thou wouldst think they were united, but their hearts are divided: that is because they are a people devoid of wisdom.”

Quran 59:14 (Yusuf Ali Translation)