the entity and function of rule compared with legal decree

governing is in need of various regulations which can be of different property from the primary decree due to the necessities, expediencies and interventional conditions.  considering the factor of “the entity of rule”, “the function of rule” and “the process of changing legal decree to the rule”, it can be understood that the entity of rule and legal decision particularly in view of criterion and expediency is considered to be different and the relationship between these two generality and specificity can be deemed to be common. in terms of function, rule is much more extended than legal decree and the legislator cares for the social values and objectives of religion besides putting emphasis on the islamic decree and he does his duty on account of them. nonetheless, due to the necessity of islamic legislation, it is needed a paradigm in order to change the legal decree to the rule in a way that the issued rules are based on the “religious principles” and the religion and needs of government are comprehensively considered in it.