Leviticus 16:3-5

3Thus shall Aaron come into the holy place : with a young bull for a sin offering, and a ram for a burnt offering. 4He shall put on the holy linen coat, and he shall have the linen breeches upon his flesh, and shall be girded with the linen waistband, and with the linen mitre shall he be attired: these are holy garments; therefore shall he wash his flesh in water, and so put them on.

5And he shall take of the congregation of the children of Israel two kids of the goats for a sin offering, and one ram for a burnt offering.