The consecration of the priests. See the notes to Leviticus 8–9.

Exodus 29:4: Door of the tabernacle - Entrance of the te…

An altar most holy. —Heb., an altar, holiness of holinesses.

Whatsoever toucheth the altar sh…

Seven days you shall make atonement for the altar, and
sanctify it
That it might be thoroughly fit to hav…

Aaron and his sons were to be set apart for the priest's office with ceremony and solemnity.