Study and analysis of the functions of al-Urf in understanding and inferring the religious rules

Religious rules in Shiite jurisprudence are inferred from the four sources of the Qur'an, Sunnah, reason and consensus. But, in addition to these sources, some foundations such as common law (al-urf) are also mentioned. Referring to common law is widely used in the words of jurists. Based on it, the question arises here: what are the roles of common law and Irtikazat in common law in understanding and inferring the religious rules? This article seeks to answer this question and tries to study and analyze the functions of common law in understanding and inferring the religious rules. The research hypothesis is that common law and Irtikazat in common law are used in understanding the words of religious arguments, subjecting and de-subjecting of common law for the religious documents, proving or denying some rights and other issues that are used by jurists and lawyers in the process of inferencing. One of the findings of the present study is that most scholars of the Islamic jurisprudence and law have not distinguished between these two foundations. But, it is more correct that common law is considered from the category of objective matter in the practical life of people, while Irtikazat in common law are from the category of subjective matter.