Sacrifice is the once-for-all self-offering of the obedient Son, who is both Priest and offering, to bring sinners into lasting access to God.
The Old Testament sacrifices pointed forward. They could cover but never finally take away sin, and they had to be repeated endlessly. Christ is the true and final sacrifice — the Lamb of God — and He is at once the Priest who offers and the offering itself.
He offered Himself once, and by that single offering He has perfected for ever those who are being sanctified, opening a new and living way into the presence of God. Because His sacrifice does not repeat, His people rest in a finished work rather than laboring to add to it.
See in Scripture: Exodus 12:1–13; Isaiah 53:7–10; John 1:29; Ephesians 5:2; Hebrews 9:11–14; Hebrews 10:10–14