How much more will the blood of Christ, who through the eternal Spirit offered himself without blemish to God, purify our conscience from dead works to serve the living God.
Hebrews 9:14

Death seems to be the source of all uncleanness. Dead bodies and dead works both defile a person.

Sacrifice and washing can temporarily remove the uncleanness of contact with physical death, but only the sacrifice and washing of Yeshua can permanently remove the uncleanness of rebellion against God's Law which brings eternal death.