AL AHZAB — Ayat 15

وَلَقَدْ كَانُوا عَاهَدُوا اللَّهَ مِن قَبْلُ لَا يُوَلُّونَ الْأَدْبَارَ وَكَانَ عَهْدُ اللَّهِ مَسْؤُولًا

And they had already promised Allah before not to turn their backs and flee. And ever is the promise to Allah [that about which one will be] questioned.