The instructions given to Aaron, the brother of Moses and the first high priest of Israel, are foundational to understanding the priestly duties and the sacrificial system established under the Mosaic Law. These instructions are primarily found in the books of Exodus, Leviticus, and Numbers, and they outline the responsibilities, rituals, and conduct expected of Aaron and his descendants, the Levitical priesthood.

Consecration and Duties

Aaron's consecration as high priest is detailed in Exodus 28-29 and Leviticus 8-9. God commands Moses to anoint Aaron and his sons, setting them apart for the priestly office. The garments of the high priest, described in Exodus 28, include the ephod, breastpiece, robe, tunic, turban, and sash, each with symbolic significance. The consecration ceremony involves sacrifices, anointing with oil, and the application of blood to Aaron and his sons, signifying purification and dedication to God's service.

Leviticus 10:8-11 provides specific instructions regarding the conduct of priests, emphasizing sobriety and discernment: "Then the LORD said to Aaron, 'You and your sons are not to drink wine or strong drink when you enter the Tent of Meeting, lest you die. This is a permanent statute for the generations to come. You must distinguish between the holy and the common, between the clean and the unclean, so that you may teach the Israelites all the statutes that the LORD has given them through Moses.'"

Sacrificial System

Aaron's role in the sacrificial system is central, as outlined in Leviticus 1-7. He is responsible for offering sacrifices on behalf of the people, including burnt offerings, grain offerings, peace offerings, sin offerings, and guilt offerings. Each type of sacrifice has specific regulations and purposes, such as atonement for sin, thanksgiving, and fellowship with God.

The Day of Atonement, described in Leviticus 16, is a significant annual event where Aaron enters the Most Holy Place to make atonement for himself, his household, and the entire congregation of Israel. This involves the sacrifice of a bull for his own sin offering and a goat for the people's sin offering, as well as the sending of a scapegoat into the wilderness, symbolically carrying away the sins of the people.

Maintaining Holiness

The instructions to Aaron emphasize the importance of holiness and obedience. Leviticus 21-22 outlines the standards for priestly conduct, including prohibitions against defilement through contact with the dead, restrictions on marriage, and requirements for physical perfection. These regulations underscore the need for the priests to be set apart as holy, reflecting God's holiness.

Numbers 18 further details the responsibilities and privileges of the priesthood, including the care of the sanctuary and the handling of offerings. Aaron and his sons are given specific portions of the offerings as their inheritance, as they have no land inheritance among the tribes of Israel.

Rebellion and Vindication

Aaron's leadership is challenged during the rebellion of Korah, Dathan, and Abiram in Numbers 16-17. God vindicates Aaron's priesthood by causing his staff to bud, blossom, and produce almonds, a sign of divine approval and selection. This event reaffirms Aaron's role and the legitimacy of the Levitical priesthood.

Legacy

The instructions to Aaron establish a pattern of worship and priestly service that points to the ultimate High Priest, Jesus Christ, who fulfills and transcends the Old Testament sacrificial system. Aaron's obedience and service set a precedent for the priesthood, emphasizing the necessity of holiness, atonement, and mediation between God and His people.