The proposition and validation of the principality of existence (Esālat al-(Wujūd) in Transcendent Philosophy contain multiple implications. Mulla Sadra identified and clarified many of these implications. However, the extraction of some of these implications and the explanation of their relationships were left to his followers. The task of uncovering the connection between some of these implications and the principality of existence has been successfully undertaken by Allama Tabataba'i and his students. Substantial motion (al-Harakat al-Jawhariyyeh) is one of the issues extensively explained in the works of Mulla Sadra and his followers; however, the dimensions of its relationship and compatibility with the principality of existence have not been independently examined. This study, utilizing the explicit statements and implied ideas of Allama Tabataba'i and his students, aims to depict the foundational connection between substantial motion and the principality of existence. First, through a demonstration per impossible on the principality of existence, we will demonstrate that the Sadrian depiction of motion in substance is justifiable only through such an assumption. Then, we will address the essence-based terminology hidden in substantial motion and consider the term intensity of existence as more appropriate for Transcendent Philosophy. Subsequently, we will present evidence of the inconsistency of motion and intensity with the principality of essence. Finally, we will conclude their foundational and essential connection, by examining the compatibility of the principality of existence with the intensity of existence and substantial motion. Considering the requirements of philosophy as its general subject, this study has processed information gathered from library sources and written documents through a descriptive-analytical method.