Although the sources of inference in Islamic jurisprudence are limited to books, traditions, consensus and reason, the rules and principles of inference and jurisprudence can be many. The jurisprudents of Imamiyyah have paid special attention to jurisprudential rules and have authored numerous works in this field. However, some of the jurisprudential rules, which are, of course, crucial to the inference, have not attracted the jurists' opinion as a rule. Although these rules have been widely used in the light of fatwas and jurisprudential arguments, they have not been codified as a rule and their boundaries have not been clearly elucidated. These are the rules of justice, the rule of equality, the principle of equality, and so on. Justice can be applied to jurisprudence as a comprehensive jurisprudential rule and eliminate the challenges of executing sentences and organize the inference of religious law based on it. In this article, to answer the question of whether the jurisprudent or jurist, especially in cases of silence, flaws, conflict of laws, or in the disagreement of scholars, can he invoke the rule of justice?, which states that there are about eighty fatwas or legal opinions in which the jurisprudent or jurist issues a "rule of justice" by issuing " Fatwa.