This article is an effort to reread the role of innate disposition in proving the existence of God in two different intellectual contexts and to represent their common and different aspects in the foundational discussions of theology in order to find a robust basis to achieve an assuring knowledge of divine propositions. This comparative study adopted a descriptive-analytical research method to attain this goal. The innateness of the knowledge about God and the demonstration of His existence along with the use of introspection in knowing God are the main common aspects between the viewpoints of Sadra and Descartes, while the difference in the type and referent of the innate knowledge and the difference in the median of the innateness arguments are the main differences of the two attitudes. The existence of difference in the philosophical system and epistemic foundations – including the Sadra’s existential originality, his belief in the direct knowledge, and his use of the revelation and mystic insight in addition to intellect – on the one hand and the essential principality and inattention to the direct knowledge and the use of pure intellect or intellectual insight by Descartes on the other hand have led to the contrast between Sadra’s mystic viewpoint to the Sublime Source and Descartes’ philosophical viewpoint and purely mathematical scale in the domain of theological discussions. Nonetheless, the similarity of some principles have led them to common and similar opinions about the possibility of knowing the Essence and the arguments about proving the essence of God based on innate knowledge.