A meal concluded the consecration of the priests because in it the priests entered into a fellowship relationship with God. This relationship entitled them to blessings and privileges that God did not grant the other Israelites.
The consecration lasted seven days. During this time the priests were not to leave the tabernacle courtyard day or night (v. 35). Their role was that of worshippers rather than priests. Evidently Moses repeated the consecration ritual on each of these seven days (v. 33). This would have emphasized its importance to Israel.
"A man may defile himself in a moment, but sanctification and the removal of uncleanness is generally a slower process."82
Note that it was God who consecrated the priests. This was His work. The "congregation"witnessed the consecration, but they did not initiate it.
The priests were responsible to wash, but God cleansed them. Confession of sin is our responsibility, but God provides the cleansing (1 John 1:9).
God did not demand perfection of the priests. He even graciously appointed the man most responsible for the Golden Calf incident to the office of high priest.
God provided the clothing (covering), the atonement, and the enablement that made the priests acceptable in their service. Likewise He provides all that we as His priests need also.
"In this section one doctrine emerges very clearly: the universality and pervasiveness of sin. The men chosen to minister to God in the tabernacle pollute the tabernacle and therefore purification offerings have to be offered. Their clothes and bodies are stained with sin and they must be smeared with blood to purify them. These sacrifices are not offered just once; they have to be repeated, because sin is deep-rooted in human nature and often recurs. There is no once-for-all cleansing known to the OT. It is the incorrigibility of the human heart that these ordination ceremonies bring into focus [cf. Ps. 14:3]."83
