Leviticus 16:5-8

Aaron must take from the community of Israel two male goats for a sin offering and a ram for a burnt offering. “Aaron will present his own bull as a sin offering to purify himself and his family, making them right with the LORD. Then he must take the two male goats and present them to the LORD at the entrance of the Tabernacle. He is to cast sacred lots to determine which goat will be reserved as an offering to the LORD and which will carry the sins of the people to the wilderness of Azazel.