The Holy Quran in verse 44 of Surah An-Nahl has introduced the Holy Prophet (PBUH) as the expounder of revelation. Accordingly, all aspects of his existence, especially the scientific aspects of his life, have been considered. Scholars of the two sects, under the topics related to the authenticity of the Prophetic tradition (PBUH) and the abrogation of the Quran through the tradition, have addressed the issue of non-Quranic revelation or expository revelation. This issue is whether the knowledge of the Holy Prophet (PBUH) originated from another source of revelation besides the Quran? Some consider it to be the result of the Prophet's ijtihad, while others consider the origin of the Prophetic knowledge (PBUH) to be a non-Quranic revelation. This research has been conducted using a descriptive-analytical method and library resources. Given that the subject has been studied in a comparative manner, the aim of this article is to examine non-Quranic revelation in the sources of the two sects, relying on the specific views of Allamah Tabataba'i and Mahmoud Aburiya. Which is referred to as Bayani revelation in Shiite sources and Sunnah revelation or unspoken revelation in Sunni sources. The results of this study are that Muslims consider the origin of the knowledge of the Holy Prophet (PBUH) to be Quranic revelation and non-Quranic revelation. Allamah Tabataba’i considers the origin of the Prophet’s (PBUH) legislation to be the result of a revelation that was revealed to him other than the Quran, and Mahmud Aburiya has questioned the removal of non-Quranic revelation from the Quran during the caliphate period with a more eloquent statement. An examination of the views of scholars of both sects makes it clear that the origin of the discussion of non-Quranic revelation regarding the Prophet (PBUH) is common among scholars of both sects.