While ample academic attention is devoted to Qur’anic hermeneutics in Islamic studies, the study of prayer supplications (du’a), aside from a few scattered encyclopedic entries, has received almost no consideration. This is despite the fact that prayer supplications form a crucial aspect of pietistic practice and spiritual orientation for Twelver Shi’a. Commentaries (shuruh) on these supplications by clerical scholars function as conduits for the latter’s comprehension and are composed in a manner intelligible to the laity who might otherwise not have the time or acumen for religious education. This article attempts to redress the absent scholarship on Shi’i devotional texts, by focusing on a commentary authored by the Qajari philosopher and poet, Mulla Hadi Sabzivari (d. 1873). Sabzivari’s commentary on the supplication Du’a al-Sabah, ascribed to Imam Ali b. Abi Talib, offers a view of Mulla Sadra-inspired metaphysics and theosophy. Du’a al-Sabah contains a series of refrains addressed to God, recognizing His superlative qualities, including, inter alia, generosity (karam), grace (lutf), and divine power (qudra). It takes the form of a repeated petition to receive a small portion of these desirable attributes from the source of their most perfect quintessence, viz. God, and a plea for forgiveness for the follies of humankind. Sabzivari’s commentary is fecund with gnostic and philosophical insight, drawing upon the supplication’s implications for ontology, the soul, God, and the Shi’a Imams, facets we analyze with regards to the supplication’s unique vernacular. I argue that where philosophical content may be otherwise impersonal and normatively inert, it becomes a direct and personal enterprise when revealed or “read into” devotional prayer. Our study suggests that prayer supplications can become conceptual channels, important for promoting particular theological themes that clerical figures wish to emphasize. In this regard, the supplications’ believed benefits (thawab) are twofold, offering comprehension of an ideal religious orientation for the supplicant and an elaboration of theocentric philosophy (hikma).