How do we know the doctrine of Christ's superior priesthood is true?

The doctrine of Christ’s superior priesthood is thoroughly established in the book of Hebrews, particularly chapters 5 through 7. It reveals that while the Levitical priests were appointed due to their weaknesses, Christ was appointed by the oath of God and has been perfected forever. This highlights that Jesus, as our High Priest, doesn't need to offer daily sacrifices for Himself or the people, because His sacrifice was once for all, securing eternal redemption. This priesthood is rooted in God’s eternal purpose, affirming its validity through the testimony of Scripture.