ٱلشَّهْرُ ٱلْحَرَامُ بِٱلشَّهْرِ ٱلْحَرَامِ وَٱلْحُرُمَـٰتُ قِصَاصٌ ۚ فَمَنِ ٱعْتَدَىٰ عَلَيْكُمْ فَٱعْتَدُوا۟ عَلَيْهِ بِمِثْلِ مَا ٱعْتَدَىٰ عَلَيْكُمْ ۚ وَٱتَّقُوا۟ ٱللَّهَ وَٱعْلَمُوٓا۟ أَنَّ ٱللَّهَ مَعَ ٱلْمُتَّقِينَ
Ash Shahrul Haraamu bish Shahril Haraami wal hurumaatu qisaas; famani'tadaa 'alaikum fa'tadoo 'alaihi bimsisli ma'tadaa 'alaikum; wattaqul laaha wa'lamooo annal laaha ma'al muttaqeen
The sacred month for the sacred month, and sanctities call for just retribution. So whoever transgresses against you, respond in kind with the like of what was done to you. Be mindful of God, and know that God is with those who are mindful of him.
The Arabic uses a single verb, iʿtadā, for the aggression and for the response, although the same root was forbidden outright a few verses earlier. Grammarians call this mushākala, matching the aggressor's own word for the sake of the parallel, and bi-mithli fixes a ceiling: the like of what was done, and no more. The closing clause on mindfulness attaches a limit to the permission just granted.