How do we know Jesus is like Melchizedek?

The comparison between Jesus and Melchizedek is rooted in the nature of their respective priesthoods. While Levitical priests were temporary and had to offer sacrifices for their own sins and the sins of the people, Jesus, as the great high priest in the order of Melchizedek, is perfect and eternal. Hebrews 7:17 states, 'Thou art a priest forever after the order of Melchizedek.' This indicates that Jesus' priesthood is unending and surpasses the limitations of the old covenant, showcasing the efficacy of His one-time sacrifice on the cross, which atoned for sin once and for all.