33:15

وَلَقَدْ كَانُوا عَاهَدُوا اللّٰهَ مِنْ قَبْلُ لَا یُوَلُّونَ الْاَدْبَارَؕ وَكَانَ عَهْدُ اللّٰهِ مَسْؤُ𐻿لًا

Walaqad kanoo AAahadoo Allaha min qablu la yuwalloona aladbara wakana AAahdu Allahi masoolan

Translations

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

Saheeh International

And verily they had already sworn unto Allah that they would not turn their backs (to the foe). An oath to Allah must be answered for

Marmaduke Pickthall