There are basically three categories of punishments in Shari`ah:

Hadd

The first is Hadd, which includes divinely prescribed forms of fixed punishment based upon the Qur'an and Sunnah. These are punishments set to preserve the public interest; they cannot be lightened nor made heavier, nor can the offender be pardoned. They instill a deep feeling of abhorrence in the society towards the crime for which the offender has been punished. Such crimes include drinking alcohol, armed robbery, theft, illicit sexual relations, apostasy, and slanderous accusations of promiscuity.

Qisas

The second form is called Qisas, which is the punishment for homicide and assault. Whenever a person causes physical harm or death to another, the injured or family of the deceased has the right to retaliation. A unique aspect of Qisas, is that the victim's family has the option to insist upon the punishment, accept monetary recompense, or forgive the offender, which could even avert capital punishment. This leaves the door open to compassion and forgiveness. Settlements are therefore encouraged outside of court, as a judge must exact the punishment.

Ta'zir

All other crimes fall into the third category, Ta`zir, which is a discretionary punishment decided by the court.

So, in the light of this, one cannot just brandish Islamic penal codes as being too harsh or inhumane while neglecting the fact that the source of those penal codes is the Mighty Lord, the Supreme Lord of the Universe. Everything with Him has been measured with absolute perfection. This perfection is reflected in the strict procedures laid down before a person can be convicted and punished. Actually, all forms of punishment stipulated by Shari`ah are more reforming and more successful in preventing recurrent crime than the man-made legal systems whose futility is proved and confirmed by daily incessant crimes, with prisons becoming homes to homosexuality and schools for harboring criminal behavior.

Based, with slight modifications, on "Punishment in Islam: An Eye For An Eye?" Al-Haramain Online Newsletter, Volume 4, Issue 8, 1st Rabi` Ath-Thani 1421 A.H. (July 2000).