One of my peers told me that faith does not require proof or logic. So, if we agree that a particular law is ordained by Allah and/or ordained by Muhammad (sws) is the last word, the question again arises whether all the laws enforced by the Sharī'ah are universal and everlasting, or for the Prophet's contemporary world. I am not an expert in the Sharī'ah nor a studious follower of the tenets of Islam, I know for certain that even during Prophet's time, the laws were slowly and progressively evolved and so many changes were made by the Rightly Guided Caliphs (rāshidūn). Do you think that our practices need revision according to the changing times and needs; and should we try to segregate permanent, universal and ephemeral, local? Is any discussion on this line is on the anvil.
Example: Our Prophet had several wives but the law restricts to four. Either the law was temporary under a given circumstances or not applicable to all.
We understand that it would not be accurate to say that the faith does not fit in reason. Islam accords to the nature. Its teachings are well established by human reason and understanding. However, the divine laws pertaining to matters where humans could not come to a decisive position are based on the Almighty's profound wisdom, and we may not be able to grasp the underlying wisdom of such laws. Take for example the matter of theft. We can understand that the crime is a very serious offence but we may fail to devise a very appropriate punishment for the offenders. Here the Divine intervenes. The Sharī'ah gives a set rule. However, the court has been given the authority to deal with the criminals considering the circumstances in which the crime is committed. This is precisely where the second Caliph, using this principle based on common sense, did not administer the prescribed punishment in the cases of theft during a famine that struck the country at that time. This I understand has led your scholars to believe that the Islamic law has evolved to its present shape.
It is also unjustifiable to say that law has evolved after the demise of the Prophet (sws). The evolution in the law during the Prophet's time was under diverse reasons. The changes brought in the law during the lifetime of the Prophet (sws) are dealt with as abrogation. A few directives have been replaced by the new ones. The basic reason for this replacement lies in the fact that human beings are naturally weak and can only accept certain decrees after training and gradual instruction.
In some instances, the society was not organized; therefore, a temporary commandment was issued which, on development of the society, was replaced with an eternal law. For example, in the beginning, it was ordered that a dying person should leave a will in order to secure the rights of all the members of his family. A tribal arbitration council used to execute punishment of fornication. All such transitory laws were admittedly superseded by lasting and eternal commandments of inheritance and prescribed punishment for fornication, when the Islamic society gained maturity.
In some cases, laws evolved and developed into their ultimate form considering the general human nature. For instance, Arabs were addicted to drinking. Therefore, initially, it was forbidden only during the prayer. As it was hard to fast in the hot and dry Arabian Desert, so atonement was allowed for the sick and the wayfarer. Later, when the people became familiar with these obligations, the permission of atonement for fasting was taken back and complete prohibition of drinking, and fasting for the whole month of Ramadan was made compulsory.
In some cases, the Prophet (saw) was allowed to put any of the decrees of previous Divine laws in practice for the time being. Later on it was also taken back and replaced with a permanent injunction of the Islamic Sharī'ah as in the matter of the direction of Prayer. It was only to test Muslims and make a clear distinction between those who follow the Prophet (sws) and those who turn on their heels in adherence to the previous traditions. Obviously this is an essential part of training.
Similarly, some laws were enforced to make up for the lack of numerical strength of the Muslims. These laws actually increased the devotion in that meager number of believers and enabled a small group of Muslims to bear more responsibilities. For example, initially all Muslims were required to offer the Tahajjud prayer at night. One Muslim fighter was initially required to face ten disbelievers in the battlefield. Alms giving was advised before having a confidential talk with the Prophet (sws) in order to strengthen and purify the Muslims. Later, when the number of Muslims increased and they grew disciplined and purified, these transitory directives were replaced with permanent ones.
Having been finalized, the religious commandments do not accept any change from anybody. It is only the prerogative of God himself to cancel any of His directives or replace it with a new one. The state and the authorities can only use the right sanctioned by the Qur'an and the Sunnah in regards to the application of the directives to particular situations. The Qur'an in fact has not fixed laws on each and every issue making it difficult for the people of the latter generations to practice them. The matters relating to social and political issues have been left upon the individuals. Islam for example does not oblige its followers to follow a set form of government. It only requires them to establish a political set up where the matters are resolved through consultation. Thus they are free to choose any system that they deem fit to their age and time.
Similarly it only prescribed punishment for a few crimes where the human intellect cannot come to a definite position and where there was always a chance of dispute. Islamic Sharī'ah has only prescribed punishment for the crimes of muharabah (crating nuisance in the land), murder and injury, qaḍaf (falsely slandering Muslim brothers), theft and fornication. The punishment ordained by the Sharī'ah in this regard is based on the divine wisdom and human minds cannot compete with that in any respect. These punishments are eternal and so are other commands.
As for the matter of the marriages of the Prophet (sws), he had additional responsibilities to fulfill. To help him discharge those obligations the Almighty allowed him to marry more women than a common Muslim could do. The Qur'an has clearly mentioned this exception. No contemporary of the Prophet ever kept more than four wives. You have rightly stated that the law was especially for the Messenger of God and not for the whole Muslim community. Our view of why the Prophet Muhammad (sws) was allowed to take more than four wives in marriage can be reached at: http://www.al-mawrid.org/Content/ViewArticle.aspx?articleId=134
However, some directives were specifically meant for the direct addressees of the Messenger of God. Fighting the rejecters among the People of the Book until they surrender and fighting the polytheists of Arabia until they are annihilated from the face of the earth is an example. For detailed analysis of the directive and its temporary and universal aspects please refer to: JIHAD
The above discussion shows that fighting people in order to establish the religion of God on a given area and annihilating the rejecters of the Messenger is no more affective. It depends on the completion of Itmaam e Hujjah (i.e. establishment of the truth removing all doubt in the minds of the people) on a specific people and we have no means to know whether a certain group has actually grasped the veracity of the message conveyed to them and that now they have knowingly rejected the message. This is because none other than God knows the true status of one's heart. Since we have no connection with God after the demise of the Prophet we cannot know when and on which group the Itmaam e Hujjah has been performed so that they should be punished for rejecting the truth. This entails that the directive to launch this kind of jihad is no longer operative. I would however reiterate the fact that jihad of course will continue to be carried out in order to combat persecution on a given community by an oppressor. However, it is only the text of the Qur'an that indicates whether a certain Shari'ah law is general or specific. We cannot wantonly decide which of the law is universal and which one is temporary. There must be explicit textual and historical evidence to prove a given assertion in this regard.
The above discussion shows that the Divine Law has been completed by the last Messenger of God. None other than God can cancel or replace his directives. No revision in the Divine law is possible after the death of the Prophet of God. There are however, spheres where the Almighty has left us with a choice as regards to the practical application of the laws which of course is entirely a different matter and should not be confused with the abrogation in the divine laws.