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.
Dimensional Analysis
Context
And if an entry had been effected to them from the sides of the (city), and they had been incited to sedition, they would certainly have brought it to pass, with none but a brief delay!
And yet they had already covenanted with Allah not to turn their backs, and a covenant with Allah must (surely) be answered for.
Say: "Running away will not profit you if ye are running away from death or slaughter; and even if (ye do escape), no more than a brief (respite) will ye be allowed to enjoy!"
Related Verses
واللهُ أعلمُ بالصَّواب