Traditional evidence is one of the most important sources of knowledge in the realm of religion. Relying on this source is related to gaining its cognitive value. Evaluation of this point depends on diagnosing the role of the traditional evidence as a producer or supporter of knowledge in various parts of religion, on the one hand, and on the other hand, it depends on studying the necessary knowledge in different parts of religion. Traditional evidence in some fields of religion, such as subsequent beliefs and parts of ethics, and most studies of jurisprudence are considered producers of knowledge, with no regard, in this concern, to any source other than traditional method. As for the role of traditional evidence in antecedent beliefs, general ethics and jurisprudence, it is confirmation. Necessary knowledge in religion is not at one level in the different parts of religion. Even in the field of beliefs, necessary knowledge is broader than certainty in the specific sense. In many philosophers’ viewpoint, conventional knowledge is considered one of the parts of knowledge as well. Therefore, traditional evidences that entail reassurance can be considered a significant source.