Qur'an 33:15

وَلَقَدْ كَانُوا۟ عَـٰهَدُوا۟ ٱللَّهَ مِن قَبْلُ لَا يُوَلُّونَ ٱلْأَدْبَـٰرَ ۚ وَكَانَ عَهْدُ ٱللَّهِ مَسْـُٔولًا

“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.”

Al-Ahzaab 33:15 · Saheeh International