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In response to the needs arisen after the establishment of the Islamic state to derive the principles of public law from jurisprudence, it is necessary to review and determine the subjects required theoretical analysis and put them at the disposal of researchers.
Entering into such fields requires the knowledge of how to derive laws from four main branches of Islamic resources and comparative studies of viewpoints of Islamic jurists. From them, the consensus of jurists should be in particular taken into account specially in respect of administrative law which is a new are of law and has no jurisprudence background. Thus, for the purpose of public law, the consensus of jurists, reasoning, and custom should be considered along with Holy Koran and Sunnah.
Among the principles of jurisprudence, the expediency is the main principle in publish law from the Islamic point of view and public law in Islam tries to avoid any conflict between the interest of people and the government