"O you who believe! Al- Qisas (the Law of Equality in punishment) is prescribed for you..." (V.2:178) Sahih al-Bukhari 4499
Arabic hadith text
حَدَّثَنَا مُحَمَّدُ بْنُ عَبْدِ اللَّهِ الأَنْصَارِيُّ، حَدَّثَنَا حُمَيْدٌ، أَنَّ أَنَسًا، حَدَّثَهُمْ عَنِ النَّبِيِّ صلى الله عليه وسلم قَالَ "كِتَابُ اللَّهِ الْقِصَاصُ "
Translation
Narrated Anas
The Prophet (ﷺ) said, "The prescribed Law of Allah is the equality in punishment (i.e. Al-Qisas)." (In cases of murders, etc.)