Muslims should know that the prescribed penalties of Shari`ah (hudud) are among the matters that are determined by the Qur’an and Sunnah and there is no room for ijtihad or personal opinion, and there is a divine wisdom behind them. For example, Allah made the prescribed penalty for theft cutting off the organ used for stealing, namely the hand; unlike adultery, whose penalty is not cutting off the organ used for committing it, but either scourging or stoning to death. On the other hand, disbelief is a more hideous sin than adultery, yet Allah did not set a certain penalty for false accusation of disbelief, though baseless accusation of disbelief is unanimously agreed upon to be prohibited. Still, Allah set a legal penalty for baseless accusation of adultery, which is not as grave as disbelief. Thus, prescribed penalties in Islam are dependent in a way that observes the people’s interests.
Ibn Al-Qayyim, in his book I`lam Al-Muwaqqi`in said: It is known that an illegal gaze cannot entail the prescribed penalty for adultery, nor can a scar by a little stick entail the prescribed penalty for a cut by a sword, nor can a slight insult entail the prescribed penalty for baseless accusation of adultery or vilification of lineage, nor can stealing a morsel or a fils [1/1000 of a dirham or dinar] entail the legal penalty for stealing a large property. When the levels of crime vary, there must be variance in the levels of penalty. It is known as well that if people relied on their minds in this concern and specified a certain penalty for each crime according to its type, description, and degree, there would be a great difference in opinion, dissention, and disagreement. However, Almighty Allah spared them such a burden and, through His wisdom, knowledge and mercy, defined crime with regard to its type and degree, and set a suitable legal penalty and an appropriate exemplary punishment for each crime. In addition, due to the limitlessness of His mercy and grace, He has made such legal penalties means of expiation and purification for the wrongdoers from the burden of sin if they willingly accept them, especially if they are followed by true repentance and sincere remorse. Thus, such prescribed penalties represent a kind of divine mercy toward the perpetrators in this world as well as in the Hereafter. Moreover, out of the perfection of His wisdom and mercy, Allah never punishes the doers in this world baselessly without manifest evidence, just as He never does in the Hereafter. The evidence can be confession or anything equivalent, such as the status of the doer, which is a clearer and more reliable proof than confession.
To illustrate furthermore, those whose present condition testifies against them—such as the smell of alcohol coming from the mouth or the vomit of a drunkard, or the presence of the stolen property at the house of the stealer or in his possession— are more deserving of punishment than those against whom confession, which could be true or false, is the only evidence. This is agreed upon among the Prophet’s Companions, though it is disputable among some jurisprudents. The evidence could be unrelated to the doer, that is the testimony of witnesses. Still, such testimony requires justice and impartiality as preconditions. In fact, the best minds can by no means set such just prescribed penalties, and if they were to suggest, they could not suggest better, more suitable, or more efficient penalties.