The truth of revelation has always been the scholars’ concern, and the study on how prophets and their Imams gained knowledge can be considered as a step in explaining this truth. Using a descriptive-analytical method, this study examines Mulla Sadra’s and Allameh Tabataba’i’s views on how prophets and Imams gained knowledge. The connection and union from the existential intensity of the prophet’s or Imam’s soul with the active intellect are considered as the origin of the infallibles’ knowledge by Mulla Sadra. He could explain how prophets and Imams gained knowledge based on the principles of transcendental wisdom, but his view was not without problems. Allameh Tabataba’i, while benefiting from the principles and concepts of transcendental wisdom, was able to compensate for the shortcomings of Sadra’s view by using the verses of the Holy Qur’an methodically and analyze it in a way that is more compatible with religious texts, verses and traditions. The findings of this study include setting forth some shortcomings of Mulla Sadra’s viewpoint and explaining Allameh Tabataba’i’s method in analyzing the Infallibles’ knowledge.