Leviticus 16:7-9

16:7 He must then take the two goats and stand them before the Lord at the entrance of the Meeting Tent, 16:8 and Aaron is to cast lots over the two goats, one lot for the Lord and one lot for Azazel. 16:9 Aaron must then present the goat which has been designated by lot for the Lord, and he is to make it a sin offering,