Suhrawardī, drawing on the concepts of light, illumination, and inner purity, demonstrates that intuitive apprehension of truth is possible only through inner purification and spiritual discipline. The luminosity of the human rational soul in Illuminationist philosophy is grounded in an ontological system of light and degrees of immateriality. Suhrawardī regards purification and refinement of the soul as a necessary condition for attaining the soul’s perfection and luminosity, and this refinement is based on self-knowledge (maʿrifat al-nafs). He advocates self-knowledge as a preliminary step toward knowledge of God. Drawing on Suhrawardī’s primary texts, this article seeks to examine the place of purification and refinement in the process of enhancing the luminosity of the soul and to analyze its relationship with self-knowledge, worship, spiritual discipline, and the Illuminationist path. It also demonstrates that the realization of luminosity in the soul does not occur through mental concepts, but rather through the purification of the inner self, practical piety, and connection with the divine lights. Employing a descriptive-analytical method and based on a study of Suhrawardī’s works, this research examines the relationship between purification of the soul and the degrees of existential perfection in Illuminationist philosophy. The findings indicate that, within Suhrawardī’s system of luminosity, purification of the soul is a necessary condition for the manifestation of the Light of Lights (Nūr al-Anwār) and for connecting to the higher degrees of existence. Without it, the attainment of ultimate perfection and true wisdom is impossible.