Qur'an 2:178

يَـٰٓأَيُّهَا ٱلَّذِينَ ءَامَنُوا۟ كُتِبَ عَلَيْكُمُ ٱلْقِصَاصُ فِى ٱلْقَتْلَى ۖ ٱلْحُرُّ بِٱلْحُرِّ وَٱلْعَبْدُ بِٱلْعَبْدِ وَٱلْأُنثَىٰ بِٱلْأُنثَىٰ ۚ فَمَنْ عُفِىَ لَهُۥ مِنْ أَخِيهِ شَىْءٌ فَٱتِّبَاعٌۢ بِٱلْمَعْرُوفِ وَأَدَآءٌ إِلَيْهِ بِإِحْسَـٰنٍ ۗ ذَٰلِكَ تَخْفِيفٌ مِّن رَّبِّكُمْ وَرَحْمَةٌ ۗ فَمَنِ ٱعْتَدَىٰ بَعْدَ ذَٰلِكَ فَلَهُۥ عَذَابٌ أَلِيمٌ

“O you who have believed, prescribed for you is legal retribution for those murdered - the free for the free, the slave for the slave, and the female for the female. But whoever overlooks from his brother [i.e., the killer] anything, then there should be a suitable follow-up and payment to him [i.e., the deceased's heir or legal representative] with good conduct. This is an alleviation from your Lord and a mercy. But whoever transgresses after that will have a painful punishment.”

Al-Baqara 2:178 · Saheeh International