How do we know Jesus is a priest forever after the order of Melchizedek?

The concept of Jesus as a priest after the order of Melchizedek is crucial in understanding His unique role in salvation history. Unlike the priests from the line of Aaron, who were limited by genealogy and mortality, Melchizedek's priesthood in Genesis is noted for its lack of recorded beginning or end, symbolizing an eternal priesthood. In Hebrews 7:3, this idea is pivotal as it establishes Jesus' eternal priestly role, which fulfills and surpasses the Old Testament sacrificial system. Jesus' priesthood is not bound by the law of sin that required continual sacrifices but is rooted in the perfect, once-for-all sacrifice that He made for His people.