That is why he is obligated to offer sacrifices for his own sins, as well as for the sins of the people.

Leviticus 9:7
Then Moses said to Aaron, "Approach the altar and sacrifice your sin offering and your burnt offering to make atonement for yourself and for the people. And sacrifice the people's offering to make atonement for them, as the LORD has commanded."

Leviticus 16:6
Aaron is to present the bull for his sin offering and make atonement for himself and his household.

1 Corinthians 15:3
For what I received I passed on to you as of first importance: that Christ died for our sins according to the Scriptures,

Hebrews 7:27
Unlike the other high priests, He does not need to offer daily sacrifices, first for His own sins and then for the sins of the people; He sacrificed for sin once for all when He offered up Himself.

Hebrews 9:7
But only the high priest entered the second room, and then only once a year, and never without blood, which he offered for himself and for the sins the people had committed in ignorance.

Hebrews 10:12
But when this Priest had offered for all time one sacrifice for sins, He sat down at the right hand of God.

And by reason hereof he ought, as for the people, so also for himself, to offer for sins.