Hebrews 9:12-14, 16, 26

and not through the blood of goats and calves, but through His own blood, He entered the holy place once for all, having obtained eternal redemption. For if the blood of goats and bulls and the ashes of a heifer sprinkling those who have been defiled sanctify for the cleansing of the flesh, how much more will the blood of Christ, who through the eternal Spirit offered Himself without blemish to God, cleanse your conscience from dead works to serve the living God?

For where a covenant is, there must of necessity be the death of the one who made it.

Otherwise, He would have needed to suffer often since the foundation of the world; but now once at the consummation of the ages He has been manifested to put away sin by the sacrifice of Himself.