In order to protect the five important indispensables in Islam:
1. religion
2. life
3. intellect
4. offspring
5. property
Islamic Law has provided a worldly punishment in addition to that in the hereafter. Islam has, in fact, adopted two courses for the preservation of these five indispensables:
the first is through cultivating religious consciousness in the human soul and the awakening of human awareness through moral education;
the second is by inflicting deterrent punishment, which is the basis of the Islamic criminal system.
Therefore "Hudud," Retaliation (qisas) and Discretionary (Tazir) punishments have been prescribed according to the type of the crime committed.
Source: http://www.muhajabah.com/docstorage/hudud.htm
The penal laws of Islam are called Hudud in the Hadith and Fiqh. This word is the plural of Hadd, which means prevention, hindrance, restraint, prohibition, and hence a restrictive ordinance or statute of God, respecting things lawful and unlawful.
Punishments are divided into two classes, one of which is called Hadd and the other Ta'zir.
The Hadd is a measure of punishment defined by the Qur'an and the Sunnah. (this is why corruption not in Hudud.)
In Ta'zir, the court, is allowed to use its discretion in regard to the form and measure in which such punishment is to be inflicted.
Punishments by way of Hadd are of the following forms: death by stoning, amputation of a limb or limbs, flogging by one hundred or eighty strokes. They are prescribed respectively for the following offences: adultery committed by married persons, theft, highway robbery, drunkenness and slander imputing unchastity to women.
The punishments described above are the maximum punishments for the above mentioned crimes. These can be reduced keeping in view the circumstances in which the crimes were committed, the nature of the evidence, and the motive of the criminal with which he committed the crime.
Source: http://www.iium.edu.my/deed/hadith/muslim/017_smt.html
