The body of law dealing with wrongs that are punishable by the state with the object of deterrence is known as criminal law. Islamic criminal law recognizes three categories of these wrongs. The first is the ḥudūd (plural of ḥadd, a “limit” set by God), the contravention of which leads to a prescribed and mandatory penalty. The second, taʿzīr (chastisement), comprises those crimes not included among the ḥudūd because their punishment is discretionary. Taʿzīr implies the correction or rehabilitation of the culprit; hence, punishment is left to the judge and might vary depending upon who inflicts it and upon whom it is inflicted. The third category, qiṣāṣ (retribution), is concerned with crimes against the person such as homicide, infliction of wounds, and battery. Punishment by retribution is set by law, but the victim or his next of kin may waive such retribution by accepting blood money or financial compensation (diyah) or by forgoing the right altogether. Because of this waiver, it has been suggested that this crime is in the nature of a private injury, more akin to a tort than to a crime involving a public interest or concern.

Jurists have accorded ḥudūd much attention because they are grounded in the Quran and the ḥadīth, as is qiṣāṣ. Taʿzīr, however, because of its discretionary nature, has escaped precise definitions and detailed treatments of the elements of the crimes that it encompasses. It might be said, though, that all acts that violate private or community interests of a public nature are subject to taʿzīr; it was left to public authorities to establish rules, within the spirit of the shariah, to punish such acts. Taʿzīr comprised essentially two categories of crimes. The first consisted of those crimes that did not meet the strict requirements of ḥudūd crimes (although they were of the same nature) or those individual crimes that were included in ḥudūd. Examples of the former are thefts among relatives or thefts of things below a minimum value for a ḥadd punishment: attempted robbery, attempted fornication, and lesbian contacts. Examples of the latter type are breach of trust by a testamentary guardian, false testimony, and usury. The second category included those acts that generally caused damage to the public order or public interest or threatened to cause such damage. In the nature of things, the second category, if not kept in check, could result in precautionary measures that might compromise individual rights; therefore, a balance had to be maintained between public order and individual rights. Punishment for taʿzīr could range from the (exceptional) death penalty for espionage and heresy, to whipping, imprisonment, local banishment, and fines for a variety of crimes. Jurists were careful, though, to limit whipping to a level below that ordered for ḥudūd punishments.

Qiṣāṣ (talion) encompassed five crimes: murder or intentional killing, quasi-intentional killing or voluntary manslaughter (as when a person intends only to beat another but in doing so kills him), involuntary killing, intentional physical injury, and unintentional physical injury. Talion (retaliation) was allowed only in instances of intentional killing and intentional physical injury; even here retribution could be waived by the victim or his family, and monetary compensation (diyah) could be exacted instead. For other qiṣāṣ crimes only monetary compensation was exacted. The diyah for killing was set by most jurists at one hundred camels or one thousand gold dinars; the diyah for physical injuries varied according to the nature of the injury. The law of qiṣāṣ was an exception to the principle of individual responsibility for crimes emphasized by Islamic law, because it made the perpetrator 's clan (ʿāqilah) responsible with him for payment of the diyah; correspondingly, the clan of the victim divided up the diyah payable for his death in keeping with the legal maxim that liability is proportional to the benefit. In later years when Arabs settled in military camps outside Arabia (amṣār), the ʿāqilah became the military unit (dīwān) to which the killer or the victim belonged. In theory all these offenses were to be tried by the qāḍī, the shariah judge. Law books throughout the centuries repeated this theoretical jurisdiction of the qāḍī, including the administration of criminal law. But in fact, the qāḍī must have lost criminal jurisdiction very early in the Islamic centuries. The reasons are several: first, the shariah dealt with only a limited number of crimes and their penalties, leaving a host of others ill-defined and lumped under taʿzīr; second, the law of evidence in the shariah, with its dependence only on trustworthy witnesses (ʿudūl) and admissions, and its rejection of circumstantial evidence, was too restrictive to allow for an efficient criminal system; finally, rulers of Islamic empires and states could not leave matters of crime affecting state security in the hands of religious authorities who were loyal to a body of laws over which the state had no control. All these factors gave rise to criminal jurisdictions independent of that of the qāḍī, although the latter continued to be involved in matters involving homicide and diyah, which assumed the character of a tort or a civil claim. As a result, the shurṭah (police) assumed the duty of investigating, prosecuting, and sentencing for most crimes with no distinction between one function and the other. The muḥtasib (inspector of the marketplace) punished those trade infractions and offenses against morals that were apparent and did not require testimony before a qāḍī 's court. In addition, beginning in the early years of the ʿAbbāsid regime in the latter part of the eighth century, a new jurisdiction, called maẓālim (court of grievances) headed by the ruler, vizier, or governor, undertook to repress wrongdoers whom other courts could not control and generally to restrain oppression by officials. None of these jurisdictions was limited by the shariah, as the qāḍī was. They applied mainly to customary law (ʿurf) or what political expediency (siyāsah) required; punishments were often arbitrary and severe.

The Ottoman sultans who inherited this system attempted to limit the arbitrary punishments meted out by these extra-shariah jurisdictions by issuing regulations (qānūn, modern Turkish kanun) for secular criminal provisions and procedures. Yet a qānūnnāme (modern Turkish kanunname), or basic law, issued in 1525 for Egypt, a few years after its conquest, seems to indicate that the purpose was to give leeway to non-shariah judges to inflict heavy punishments for disputes and feuds that qāḍīs could not suppress.

Ref: Oxford Islamic Studies Online, Idézet a büntetőjogról Ziadeh, Farhat J. "Büntetőjog". Iszlám Világ. Oxford Enciklopédia. Oxford Iszlám Tanulmányok Online. 2020. március 5.
http://www.oxfordislamicstudies.com/article/opr/t236/e0170