In his humanity, Jesus was not literally a priest; that is, as a member of the tribe of Judah, he was not of the line of Levi and did not serve in the Jerusalem temple as one of its priests. Yet the author of the Letter to the Hebrews famously calls him “high priest,” and “of the order of Melchizedech.” What does this mean? The author is using a powerful metaphor, borrowed from Psalm 110:4, to capture the reality that, like the high priest performing the ritual of the Day of Atonement, Jesus functioned as a mediator between God and the people of God, facilitating reconciliation through a sacrifice, in Jesus’ case through self-sacrifice.

Notice how the incarnation plays an integrating role here; as both divine and human, Jesus is uniquely qualified to function as a mediator, since he participates in both the divine and human reality. He can be said to “learn” obedience because, as human, he did indeed learn what human obedience of God is by undergoing the human experience of obeying the will of the Father. Similarly, the author can also say that Jesus is “made perfect,” for through his experience of human suffering he becomes more perfect in his role as mediator. By suffering, he grows in solidarity with human beings. In that way he also enables human persons to be saved by their obedience to Jesus.

And what does it mean to be “of the order of Melchizedech”? As the author states later about Melchizedech, in chapter  seven, “Without father, mother, or ancestry, without beginning of days or end of life, thus made to resemble the Son of God, he remains a priest forever” (7:3). That is the author’s way of saying that Melchizedech is an anticipation of Jesus who has those qualities in a transcendent way, now that he is risen Lord.

This exotic (to us) use of metaphor is a very Jewish way of reminding us Christian readers that Jesus really did become one of us, to help up connect with the divinity that he also embodies as incarnate Son, now risen. We participate in that growing union every time we celebrate the Eucharist, when we participate in Jesus’ self-offering to the Father in union with the Holy Spirit.