How do we know the doctrine of Christ's dual nature is true?

The doctrine of the dual nature of Christ, being both fully God and fully man, is rooted in various biblical passages and affirmed throughout church history. Key Scriptures like John 1:14 declare, 'And the Word was made flesh, and dwelt among us,' which explicitly testifies to the incarnation of Christ. Additionally, His titles, such as 'God with us' (Isaiah 7:14) and 'the man Christ Jesus' (1 Timothy 2:5), affirm both His divine and human aspects.

Historically, this doctrine has been integral to the Reformed faith, outlined in creeds such as the Chalcedonian Definition, which states that Christ is recognized in two natures, unconfusedly, unchangeably, indivisibly, and inseparably. The Council of Chalcedon (451 AD) fought against heresies that denied either His true humanity or true divinity, emphasizing that both natures exist in the one person of Christ. Thus, the biblical evidence combined with historical affirmation provides a robust foundation for this doctrine.