How do we know Christ as our priest is true?

The certainty of Christ's priesthood is rooted in His fulfillment of the Old Covenant's requirements, where the Old Testament indicated the necessity of a priest making sacrifices. Christ, as the ultimate priest, offered Himself as the perfect sacrifice. Hebrews reminds us that unlike the Levitical priests who had to repeatedly offer sacrifices, Christ's offering was one and final, which ensures our redemption permanently. This definitive achievement is what gives us assurance in His priestly role.