Leviticus 9

On the eighth day after their consecration, Aaron and his sons officially begin their priestly duties. Aaron offers the required sin and burnt offerings for himself and the people. When Aaron finishes sacrificing and blesses the people, the glory of the Lord visibly appears to the whole congregation. A fire comes out from the presence of the Lord and consumes the offerings on the altar, confirming God's acceptance of Aaron and the newly instituted sacrificial system.