Kenneth M. Wilson has argued that Augustine innovated the concept of “demonic faith” and that his influence has caused interpreters to misconstrue the diatribe found in Jas 2:18–20. Wilson reads the interlocutor's speech as continuing through verse 19 and concludes that the statement about the demons believing does not come from the author of James. I respond to this reading by critiquing Wilson's assertions about the ancient rhetorical form diatribe, clarifying the meaning of the verb πιστɛύω, tracing the argument of the passage and showing how verse 19 fits within it, and giving attention to larger thematic resonances in the epistle. Of particular importance is a passage about two types of wisdom (3:13–18); one type, labeled demonic, provides an interpretive parallel for the statement in 2:19 that “the demons believe.” I seek to advance the conversation about the unity of the epistle by demonstrating how the themes of faith and wisdom resonate throughout chapters 1–3. In the Jacobean perspective, there are genuine forms of faith and wisdom that are gifts from above as well as deficient forms of each that are connected with the demonic realm. In this light, it makes sense to read the statement about the demons believing as part of the author's argument rather than an objection from the interlocutor.