Leviticus 16:15-17

15“Then he shall kill the goat of the sin offering that is for [the sins of] the people and bring its blood within the veil [into the Most Holy Place] and do with its blood as he did with the blood of the bull, and sprinkle it on the mercy seat and in front of the mercy seat.

16So he shall make atonement for the Holy Place (Holy of Holies) because of the uncleanness and transgressions of the Israelites, for all their sins. He shall also do this for the Tent of Meeting which is among them in the midst of their uncleanness (impurities).

17There shall be no person in the Tent of Meeting when the high priest goes in to make atonement in the Holy Place [within the veil] until he comes out, so that he may make atonement for himself (his own sins) and for his household and for all the congregation of Israel.