Aaron, the brother of Moses, holds a significant role in the religious life of the Israelites as the first high priest. His responsibilities for the sanctuary are outlined primarily in the books of Exodus, Leviticus, and Numbers. As the high priest, Aaron was entrusted with duties that were central to the worship and spiritual life of the Israelite community.

Appointment and Role:

Aaron's appointment as high priest is divinely ordained. In Exodus 28:1 , God commands Moses, "Bring near to you your brother Aaron and his sons with him, from among the Israelites, to serve Me as priests—Aaron, Nadab and Abihu, Eleazar and Ithamar, Aaron’s sons." This appointment establishes Aaron and his descendants as the priestly line responsible for the sanctuary.

Duties in the Sanctuary:

Aaron's primary responsibilities included overseeing the offerings and sacrifices, maintaining the sanctity of the sanctuary, and interceding on behalf of the people. Leviticus 16 details Aaron's duties on the Day of Atonement, a critical aspect of his role. He was to enter the Most Holy Place once a year to make atonement for himself and the people, as described in Leviticus 16:32-34 : "The priest who is anointed and ordained to succeed his father as high priest is to make atonement. He is to put on the sacred linen garments and make atonement for the Most Holy Place, the Tent of Meeting, and the altar, as well as for the priests and all the people of the assembly."

Guardianship of the Sanctuary:

Aaron and his sons were charged with the guardianship of the sanctuary. Numbers 18:1-7 outlines this responsibility, emphasizing the importance of maintaining the holiness of the sanctuary and the priesthood. Verse 7 states, "But only you and your sons may serve as priests in connection with everything at the altar and inside the veil, and you are to perform the service. I am giving you the priesthood as a gift. But the unauthorized person who approaches must be put to death."

Symbolic and Mediatorial Role:

Aaron's role as high priest also carried symbolic significance. He acted as a mediator between God and the Israelites, bearing the names of the tribes of Israel on the breastpiece of judgment over his heart when he entered the Holy Place, as described in Exodus 28:29 : "Whenever Aaron enters the Holy Place, he shall bear the names of the sons of Israel over his heart on the breastpiece of judgment, as a continual reminder before the LORD."

Consecration and Holiness:

The consecration of Aaron and his sons is detailed in Exodus 29 and Leviticus 8, where specific rituals and sacrifices are prescribed to sanctify them for their priestly duties. This consecration underscores the holiness required of those who serve in the sanctuary, as they are set apart for the service of God.

Challenges and Failures:

Despite his high calling, Aaron faced challenges and failures. Notably, in Exodus 32, Aaron succumbs to the people's demands and fashions a golden calf, leading to idolatry. This incident highlights the human frailty even among those chosen for sacred duties.

Legacy:

Aaron's legacy as the first high priest is foundational for the Israelite priesthood. His responsibilities for the sanctuary set a precedent for the Levitical priesthood and the centrality of worship in the life of Israel. His role is a precursor to the ultimate high priesthood of Jesus Christ, as described in the New Testament book of Hebrews, which draws parallels between Aaron's priesthood and the eternal priesthood of Christ.