وَلَقَدْ كَانُوا عَـٰهَدُوا ٱللَّهَ مِن قَبْلُ لَا يُوَلُّونَ ٱلْأَدْبَـٰرَ ۚ وَكَانَ عَهْدُ ٱللَّهِ مَسْـُٔولًا

Walaqad kanoo AAahadoo Allahamin qablu la yuwalloona al-adbara wakanaAAahdu Allahi mas-oola

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