How do we know that Christ is the head of the new creation?

In the New Testament, Christ's authority as the builder of the Church is affirmed in Matthew 16:18, where He declares that He will build His Church. This indicates His governing authority over the Church as its Lord. Hebrews 3:3-5 reinforces this idea by comparing Christ's glory in building the house of God, signifying that He holds ultimate authority and preeminence over all. Thus, as the first-born who has defeated death, Christ is not only foundational to the new creation but actively sustains and directs it.