This study is an attempt to find one of the main sources of Mulla Sadra's Intellectual-philosophical foundations. Mulla Sadra's ontology configuration, relying upon simplicity, unity of right of reality, existence influence, etc. corresponds to the statements of Imam Ali (PBUH) in the description of Allah, the Almighty, in Nahj al-Balaghah including such features as absoluteness, non-numerical unity, negating dualism of God and the disjunction from existences etc., in a way that the theology of Imam Ali (PBUH) may be regarded as one of the main elements of the configuration of Shiite intellect as well as the basis of Mulla Sadra's ontology...