Jacob of Sarug (d. 521) was one of the great Syriac poet preachers, a master of the verse homily form known as the mimro. Many of Jacob’s mimre begin with a substantial prayer of praise and thanksgiving, a doxology invoking divine assistance for the homiletic task at hand. Often beautifully crafted, these prayers have received little scholarly attention except in their contribution towards establishing Jacob’s homiletic style and approach to biblical interpretation. This paper, by contrast, will consider these invocations from the literary and rhetorical perspectives. Jacob utilized a number of poetic conventions in these prayers that serve to establish the mimro as a particular form of ritual speech, with distinctive characteristics, rendering its presentation a sacred event. Rhetorically, Jacob’s invocational prayers served to demarcate the constituent components of preaching as an activity. With these prayers, Jacob constructed the sermon’s content, speaker, and listeners, each with critical contribution to the mimro’s form and function. The invocations established the content of the mimro as divinely conveyed instruction. Further, they constructed Jacob’s own homiletic role as that of vehicle or instrument for this instruction: the homilist as flute or harp of the Holy Spirit. Finally, these prayers also constructed the listeners – the members of the congregation, whether lay or consecrated - as themselves ritually essential and ritually distinct in the role they fulfilled for the mimro’s liturgical task. In Jacob’s prayers, the congregation was summoned to active reception of the poet preacher’s divinely inspired words, thereby themselves rendering praise and glory.