The High Priest Was Personally Clean
Leviticus 16: 4, 6
Aaron had to wash and make an offering for his sin so that when he entered before God he was ceremonially clean. This typified the holiness of Christ Jesus who was born of the Spirit. He was proven righteous under the law of God as the Representative of his people (Hebrews 7: 26-28.) Christ was personally, every wit, clean.