The issue of the authority of reason from the point of view of Islam is fixed in its place and Islamic scholars have not doubted it from the beginning until now and have considered it as one of the four sources of jurisprudence. The authority of the intellect is also proved by the intellect. Accordingly, the purpose of this study is to investigate the authority of reason from the perspective of religious sources. Leading research has been done by library method and study of books and articles in the fields of jurisprudence, principles and theology. Studies have shown that one of the things that can express the authority of reason is intellectual knowledge; Which is a conceptual knowledge of fixed facts that also cover the changing and moving affairs of the natural world. The Almighty God in the Qur'an often calls man to walk on earth and reflect on the life situation of some people and their fate due to sins. Another reason that indicates the originality of reason is that it expresses issues in their causal relationship. In line with the authority of reason, it is necessary to remember that God created man with the power of thought and intellect to worship God by thinking about creatures; If he does not use this God-given power well and in the right direction, he has sinned against God. The commission of sins is incompatible with the purpose of His creation, so God has sent the heavenly laws to guide mankind.