ذَٰلِكَ وَمَنْ عَاقَبَ بِمِثْلِ مَا عُوقِبَ بِهِۦ ثُمَّ بُغِىَ عَلَيْهِ لَيَنصُرَنَّهُ ٱللَّهُ إِنَّ ٱللَّهَ لَعَفُوٌّ غَفُورٌ
Dhālika wa man ʿāqaba bi-mithli mā ʿūqiba bihi thumma bughiya ʿalayhi la-yanṣurannahu'llāh · Inna'llāha la-ʿafuwwun ghafūr
"So it is. Whoever requites with the like of what was done to him and is then assaulted again, God will surely help him. God is much pardoning, much forgiving."
At the centre of the sentence stands a note of equivalence: bi-mithli mā ʿūqiba bih — "with the like of what was done to him".
I record this as an observation about word order: the requital is not left free; its measure is the thing that came. And the measure is bound not to the discretion of the one who requites but to what was done to him.
And there is a second step in the conditional clause: thumma bughiya ʿalayh — "then he was assaulted again". The promise, then, is tied not to the first requital but to the assault continuing after the requital.
بَغَىٰ — root ب-غ-ي: to want, to seek; and to exceed the bound. Both branches of the sense are recorded by the lexicographers; baghy is a wanting that goes past the limit.
This is a striking pairing, and I record it as my own reading, its ground being that the two sentences stand side by side:
The sentence acknowledges a right to requite. And at the close it names pardon. Two things in one verse: the acknowledging of a right and the recalling of pardon.
The verse imposes no preference between the two. The requital is counted lawful, and pardon is named as well. And this is of the same kind as the measure recorded at al-Baqara 2/203: there too two choices (to hasten, to stay behind) ended in an equal ruling.
عَفُوّ — root ع-ف-و: to wipe away, to efface the trace of. It is used of the wind's effacing tracks in the sand. غَفُور — root غ-ف-ر: to cover. Mighfar (the head-covering) is of the same root.
The difference between the two attributes is worth recording, and the lexicographers give it thus: ʿafw effaces the trace; ghufrān covers it over. One destroys, the other conceals. I transmit this distinction as it is transmitted.