Leviticus 9:2

And he said unto Aaron, take thee a young calf, a bull calf, or very young bullock, for a sin-offering, and a ram for a burnt offering, without blemish, and offer them before the Lord. These first offerings of Aaron were made altogether under the directions of Moses as the mouthpiece of God, for he was just entering upon his office. The fact that Baron, in spite of the consecration with all its sacrifices, still began the work of his ministry with a sin-offering and a burnt offering, shows plainly that the sacrifices of the Old Testament cultus cannot make those perfect that offer them, Hebrews 10:1. The temporary, the typical and symbolical character of the ancient sacrifices appears throughout.