This essay focuses on two anti-Jewish chapters from the ninth-century Zoroastrian apologetic-polemical book called the Doubt-Dispelling Exposition (Škand Gumānīg Wizār). This book represents the earliest sustained engagement of Zoroastrianism with Judaism and Jewish texts. Through a close analysis of the text, this essay demonstrates how the author of this complex work, who synopsizes Genesis 1–3 and some other passages from the Bible and rabbinic literature, focuses his attack on the inconsistencies and internal contradictions in how the “First Scripture” describes God’s power over creation, His intentions, and human free will. While this paper focuses on the contents and form of the Škand Gumānīg Wizār itself, it also alludes to the broader historical and intellectual environment in which the author, an educated Zoroastrian layman in search of religious truth, was operating in early Islamic Iran.