Theological arguments established that Islam does have a universal fixed economic system. Otherwise, human beings are not sufficiently guided to prosperity and salvation. Several sayings emphasizing that Islamic Sharia is comprehensive also support this idea. A glance at the regulations and laws legislated by God show that Sharia does possess an economic system. Saying that Islamic Sharia is fixed amounts to saying that there are mechanisms in Sharia law for leading the changes emerging in the real conditions of life in the direction ideal from the point of view of Islamic values and objectives. We can derive behavioral patterns and the structure of relations among economic groups from the fixed universal Islamic legal and ethical judgments. A systematic study of Islamic jurisprudence would indicate that behavioral patterns pertinent to consumption, investment, production, and saving suitable to Muslim individuals and society can be defined. Also, it is possible to define the type of economic relations between several groups of people in different markets suitable to the Islamic view. The kind of relation between the private sector and state can be defined on the basis of general principles of Islamic jurisprudence. In this way, Islamic economic system can be introduced to modern man in the language understandable in the modern age. This requires systematic research by experts in Islamic economics.