The status of legislation of the Prophet (s) and Imams (a) have been questioned and denied by some. The religious sources, including verses and traditions, show that the Prophet (s) and Imams (s) have such a position gifted to them by Allah Almighty. The present research was conducted with an approach to the opinions held by al-Shaykh Muhammad Jawad Fazel Lankarani on the legislative status of the Prophet (s) and Imams (s). The article employs an analytical method using library resources. After examining and responding to the arguments of the deniers of the legislation by the Prophet (s) and Imams (a), the author concedes the delegation of legislation to the Prophet (s) and the Imams (a), and expresses his interpretation of what this delegation was. He terms it as the existence of authority vested in the Prophet (s) and Imams (a). Therefore, the Prophet (s) and the Imams (s) are knowledgeable about all the requirements, and their legislation is such that if God Almighty wants to make legislation on the same subject, He will not legislate and dictate other than the Prophet (s) and Imams (a) legislated.