In this article I argue that the integration of biblical exegesis and metaphysical argumentation in Turretin's doctrine of God is due to his views in epistemology and semantics. Anyone reading Turretin's Locus de Deo will recognize that it is not limited to scriptural exegesis and exploration of biblical concepts. The biblical orientation is, of course, prominent, but in addition he combines it with logic and metaphysics. I argue that by adhering to an instrumental view of reason, and an analogical or partially univocal theory of theistic reference, he is able to construct a concept of God which draws first and foremost on the Christian canon and in addition on logic and metaphysics.