The importance of the holy Shari'ah of Islam is crucial. By means of it, human beings know exactly how to live in harmony with his or her Creator, with the rest of mankind, and with the rest of creation.
If we look at the proceedings of the material universe, we realize that the planets and forces of nature are all bound by fixed laws that ensure the material creation's symmetry. The animal world is also bound by such laws, and, even though animals are motivated only by their natural, "base", "worldly", "material" instincts, they too contribute to the symmetry and harmony of this planet.
The world of human beings, however, is a general exception to these observations. Reflection on the proceedings and the methods of human beings in the world shows that they are in no way in harmony with the symmetry of the universe around them. On the contrary, it shows them to be all but striving to disturb and disrupt that symmetry.
To the religiously minded, therefore, it should come as no surprise that God has provided, for those of His human creatures who desire to worship Him and serve Him, an orderly system whereby their lives can match the order and symmetry of the rest of creation, especially when it is borne in-mind that, now and in the future more than ever, the symmetry of the rest of creation depends on symmetry in the life of human beings. That is, if human beings do not quickly adopt the system wherein lies the means of their life becoming orderly, the system which Islam calls the Shari'ah, much of the order of the creation will vanish.
The Shari'ah of Islam in as much as it is a Shari'ah, or a system of legislation is not particular to Islam; rather in its earlier stages it was a part of the other divinely-founded religions. Noah, Abraham, Moses, and Jesus, upon them all be peace, were all commanded to convey to their followers the Shari'ah that had been perfected to the point suitable for their respective times and locations. The Shari'ah of Islam is particular to Islam, however, in that it was entrusted to the Holy Prophet for him and his followers to follow, and in that it will remain unchanged and binding on God's servants until the day of judgment.
In the Qur’an, the Holy Prophet, and, tacitly, mankind, is told: "Then we placed you on a Shari'ah of the affair (religion), so follow it." (45:18) And, whatever the circumstances in which this verse was revealed, the meaning of the word Shari'ah here is the same as is understood today, i.e. the divine legislation of Islam.
In another place the Prophet is told to. tell his followers: "If you love God, follow me; God will love you." (3:30)
From these two verses the Muslim realizes that it is incumbent on those who desire to obey God and to be loved by God to follow the Shari'ah of Islam as introduced and practiced by the Holy Prophet and his true followers. The only problem is the determining of the Shari'ah, for the Shari'ah was not revealed for mankind as the Qur’an was revealed, and unless the Shari'ah is properly identified it can never be properly followed.
This identifying of the Shari'ah, then, in the light of the Qur’anic command to follow it, is the purpose of the two Islamic sciences of Jurisprudence (fiqh) and the Principles of Jurisprudence (usul ul-fiqh) which are outlined in the present translation. The aim of this work is to acquaint the reader with the Shari'ah and how it is realized.
The original book was in Persian, and in translation it has been slightly abridged to suit a different readership. The translator owes his thanks to his wife, most of all for her encouragement, and to Syed Mohammad Rizvi for his ready and valuable assistance in editing the first part of the draft. This translation is dedicated to those who will make good use of it.
—Mohammad Salman Tawheedi Qom, Islamic Republic of Iran 27th Rajab 1401
The Arabic word fiqh, translated as jurisprudence throughout the book, in order to facilitate the reading of the text, actually means, according to the author, "precise and profound deducing of the Islamic regulations of actions from the relevant sources". This definition should be kept in mind by the reader for jurisprudence in the Islamic perspective is based on the divine principles of the Holy Qur’an and are not man-made laws in the sense of western jurisprudence. In the same way, a jurisprudent (faqih) in Islamic terminology is a person trained in the traditional Islamic sciences, meaning that a jurisprudent, in this sense, is a master of the Qur’an and the divine commands regulating actions.
—Laleh Bakhtiar Shawwal, 1401