Reformed theology reads Hebrews 1:8 as proof of Christ's deity from OT Scripture. The application of Psalm 45:6 to Christ—directly addressing him as 'God' (ho theos)—demonstrates that Christ is not merely a created agent but the eternal God the Son. This passage integrates into Reformed systematic theology's doctrine of Christ as the second person of the Trinity, coequal with the Father in power and glory.

The passage provides biblical grounding for the Trinitarian confession. Calvin and Reformed commentators noted that this verse shows how OT passages appropriately refer to Christ as God, affirming the continuity between Testament revelation. Hebrews 1:8 establishes Christ's divine nature and eternal throne as presuppositions for his incarnation and mediatorial work.