This article explores the interpretation of the Qurān presented by Mullā Sadrā (d. 1050AH/1640), a mystic philosopher of Ithnācasharī Shīca Islam in Iran. First, in his Keys to the Unknown (Mafātīh al-ghayb), we know the general mechanism of how reading the Qur'ān realizes spiritual perfection. Mullā Sadrā considers the Qurān as the source of spiritual wisdom with a multi-layered structure of meaning. Through concentration on Qur'ānic texts, a reader's soul will be open to a deeper layer of meaning with an awareness of a higher level of spiritual perfection. As a concrete example, we examine his commentary on the Chapter of Earthquake (Sūrat al-Zalzalah), which depicts the catastrophic events on the Last Day. In the literal meaning, or the surface layer of meaning, he intuits as a hidden deeper meaning the incessant re-creation and dynamic flux of existence towards perfection, which also explains different transformations of human beings in the hereafter. We find here another spirituality of Islam, which differs from that of the Islam built on the surface meanings of the Qur'ān.