Qiṣāṣ (Arabic: قصاص) is an Islamic term meaning "retaliation in kind" or revenge, "eye for an eye", "nemesis" or retributive justice. It is a category of crimes in Islamic jurisprudence, where Sharia allows equal retaliation as the punishment. Qisas principle is available against the accused, to the victim or victim's heirs, when a Muslim is murdered, suffers bodily injury or suffers property damage. In the case of murder, Qisas means the right of a murder victim's nearest relative or Wali (ولي) (legal guardian) to, if the court approves, take the life of the killer.
Qisas is one of several forms of punishment in Islamic Penal Law, others being Hudud, Diyya and Ta'zir.
The Qisas or equivalence verse in Quran is,
O ye who believe! the law of equality is prescribed to you in cases of murder: the free for the free, the slave for the slave, the woman for the woman. But if any remission is made by the brother of the slain, then grant any reasonable demand, and compensate him with handsome gratitude, this is a concession and a Mercy from your Lord. After this whoever exceeds the limits shall be in grave penalty.
The Hadiths have extensive discussion of qisas. For example, Sahih Bukhari states,
Allah's Apostle said, "The blood of a Muslim who confesses that none has the right to be worshipped but Allah and that I am His Apostle, cannot be shed except in three cases: In Qisas for murder, a married person who commits illegal sexual intercourse and the one who reverts from Islam (apostate) and leaves the Muslims."
Narrated Anas: The daughter of An-Nadr slapped a girl and broke her incisor tooth. They (the relatives of that girl), came to the Prophet and he gave the order of Qisas (equality in punishment).
Qisas system of punishment is prescribed in Quran and Hadiths to any case of unnatural death (murder, manslaughter), bodily injury or aggravated assault suffered by a Muslim. However, in the history of Islam, many premodern Islamic scholars ruled that Qisas did not apply when the victim was a non-Muslim dhimmi and to non-Muslim slaves owned by a Muslim.