Leviticus 9:13
And they presented the burnt offering unto him, with the pieces thereof, and the head: and he burnt them upon the altar. And they presented the burnt offering unto him, with the pieces thereof, and the head: and he burnt them upon the altar.
Aaron presented the burnt offering with its cut pieces and its head and burned them upon the altar. This presenting and burning belonged to the service that God himself had commanded. God accepted the sacrifice offered in obedience to that command. His acceptance and glory were revealed when fire came forth from Him and consumed the offering upon the altar.