Surah Al-Baqarah, verse 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 ﴿١٧٨﴾

2:178 O you who believe, legal retribution is prescribed for you in cases of murder – a free for a free, a slave for a slave, and a female for a female. But if one is pardoned by the victim’s guardian, then a fair ransom of blood-money should be set and paid in best way. This is a concession and a mercy from your Lord. But whoever transgresses the limits afterwards, will have a painful punishment