How do we know Jesus' priesthood is better than the Old Testament priests?

The book of Hebrews asserts multiple times that Jesus' priesthood is better than that of the Old Testament priests. Unlike the Levitical priests, who were mortal and unable to continue in their roles indefinitely due to death, Jesus holds an unchangeable priesthood. Hebrews 7:24-25 explains that He continues forever and is able to save to the uttermost those who come to God through Him. His sacrifice on the cross is complete and satisfactory, fulfilling the types and shadows of the Old Testament, rendering them obsolete. By offering Himself as the perfect sacrifice, He provides an eternal atonement that no animal sacrifice could achieve, making Him the ultimate and better high priest for believers today.