In the Islamic Penal Code, the legislator has explicitly said that religious proofs have relevance. Because of this, a comprehensible study is necessary. In the present article, while referring to the opinions of Muslim Usulis, the authors introduce a consistent version of the rule of “relevance of proof”. Then, they will discuss developments occurred in the legislator’s approach to the relevance of proofs. In what follows, the will discuss the negative and positive effects of relevance of religious proofs and show the relation between it in the one hand and the judge’s knowledge and the rule of dar’a on the other. In addition, using Usuli and epistemological teachings, they will provide an argument for relevance of proofs and make use of this argument as a powerful means to reduce the cases of wrong conviction. Finally, they will conclude that, in this old rule, such a rationality can be found which is useful in the present day as well.
