Why is the concept of Jesus's unchangeable priesthood important for Christians?

The importance of Jesus's unchangeable priesthood lies in the assurance it provides to believers regarding their salvation and ongoing relationship with God. Since He ever liveth to make intercession for us, we can have confidence that our sins are fully paid for. There is no more sacrifice needed, and His work on our behalf continues. This foundational truth underscores the stability and completeness of our hope in Christ, reinforcing that we are saved completely and eternally by His perfect work.