The Two Old-Covenant Orders of Priesthood: Aaron and Melchizedek

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oday, we reflect on the two orders of priesthood—the order of Aaron and the order of Melchizedek. These two priestly orders reveal deep truths to appreciate Christ’s order of priesthood. Let us explore how these priestly orders are interconnected.

1. The Order of Aaron: A Priesthood of the Law

The priestly order of Aaron represents the priesthood under the Mosaic Law. Aaron, the brother of Moses, was chosen by God to serve as the first high priest, and his descendants were set apart to mediate between God and His people.

The Aaronic priesthood was rooted in sacrifice and atonement. The priests offered sacrifices for the sins of the people, as prescribed by the Law. However, this priesthood had limitations: First, it was hereditary, and restricted to Aaron's lineage. Unlike John the Baptist, Jesus was not from the tribe of Levi but from the tribe of Judah. (See Heb. 7:13,14.) This means that according to Mosaic law, Jesus lacked the first requirement for priesthood. Second, its sacrifices were repeated because one animal sacrifice is not enough to bring about lasting forgiveness.

Despite these limitations, the order of Aaron reminds us of the seriousness of sin and humanity's need for a mediator to restore our relationship with God.

For 1,500 years from the time of Aaron until the time when Jesus established the new covenant, all the priestly descendants of Levi continued to serve as priests according to the order of Aaron in the earthly sanctuary. What if it did not stop? Priests would have continued sacrificing to God for the people’s sins by slaughtering a lamb or goat. Second, ritual baths and stone vessels for purification would have multiplied. Archaeological evidence confirms this period’s obsession with ritual baths (מקוה mikvah) and stone vessels for purification. The Temple complex had concentric courts, with increasing restrictions on who could enter. The outermost court, the Court of the Gentiles, was open to everyone, including non-Jews. Further in, a small balustrade marked the boundary beyond which non-Jews could not pass under penalty of death—a prohibition inscribed in Greek. The full text reads, “No foreigner shall enter within the forecourt and the balustrade around the sanctuary. Whoever is caught will have himself to blame for his subsequent death.” The Holy of Holies, at the heart of the Temple, could only be entered by the High Priest, and only on Yom Kippur, after an extensive ritual purification process.

Ethiopian Christians still follow these traditions, as do some of the other Orthodox communities. You can see the priests in their white garments, checking the sharpness of the blade. This is important because, for the process to be kosher and for the animal to suffer less, the cut must be very precise and clean.

Meanwhile, the younger men who assist with the more physical aspects of the sacrifice are dressed similarly to workers in industrial butcher shops—wearing full white suits. Temple sites were essentially places where large numbers of animals were slaughtered. What does this mean? It means there was a lot to clean. Animals, sensing they were about to be slaughtered, would understandably become agitated, so it wasn’t exactly a calm process. All of this required plenty of water—not only for cleaning the area but also for maintaining the necessary ritual purity.

2. The Order of Melchizedek: A Priesthood of Promise

The order of Melchizedek is a mystery in Scripture. Melchizedek appears briefly in Genesis 14, where he is described as the "king of Salem" and "priest of God Most High." He blesses Abraham and offers bread and wine—a gesture filled with prophetic significance.

Unlike the Aaronic priesthood, Melchizedek's priesthood is not based on lineage or the Law but on a divine calling. He represents an eternal priesthood, without beginning or end (Heb 7:3). His offering of bread and wine prefigures the Eucharist, the ultimate sacrifice of Christ’s body and blood.

Melchizedek’s priesthood points us to a reality that transcends the Old Covenant—a priesthood rooted in grace and promise, not in legal obligation.

3. Jesus Christ: The High Priest Who Perfectly Fulfills Both Orders and Transcends Them

Jesus unites and surpasses these two orders of priesthood. He fulfills the Aaronic priesthood by offering Himself as the perfect sacrifice for sin. He has no need, as did the high priests, to offer sacrifice for his sins. Jesus was unblemished. He has no need to offer sacrifice day after day for the sins of the people. He did that once for all when he offered himself. His death on the cross brings the forgiveness and reconciliation that the sacrifices of the Law could only foreshadow.

At the same time, Jesus is the eternal high priest in the order of Melchizedek. His priesthood is not tied to ancestry but to His divine nature. He mediates a new covenant, offering us not the blood of animals but His own body and blood in the Eucharist. Just as Melchizedek blessed Abraham through bread and wine, Jesus blessed human beings through the sacrament of his body and blood in the form of bread and wine at the Last Supper.

We end with a prayer to Jesus in the Eucharist by St Catherine of Siena: O boundless charity! Just as You gave us yourself, wholly God and wholly man, so You left us all of yourself as food so that while we are pilgrims in this life, we might not collapse in our weariness, but be strengthened by You, Heavenly Food. Amen. Fr JM Manzano SJ