Leviticus 9:2
And he said unto Aaron, Take thee a young calf for a sin offering, and a ram for a burnt offering, without blemish, and offer them before the LORD. And he said unto Aaron, Take thee a young calf for a sin offering, and a ram for a burnt offering, without blemish, and offer them before the LORD.
The command to Aaron to take a young calf for a sin offering and a ram for a burnt offering belonged to the eighth-day service that opened after seven days spent in consecrating the priests. In that service Aaron presented the sacrifices God had required, and everything was done exactly as God had commanded. God showed His acceptance of the offering by revealing His glory, sending fire from Himself that consumed the sacrifice upon the altar. The people recognized that fire as a token of God's glory and favor, and they answered with praise and worship.