There were countless animal sacrifices made under the Old Covenant. The priests stood day after day and repeatedly offered the same sacrifices – sacrifices which could never take away the sins of those for whom they were offered. By contrast, Jesus Christ, our great High Priest, offered one sacrifice, once for all time which takes away completely and forever the sins of all who believe in Him. The priests under the Old Covenant always stood, for their work was never finished. Speaking of Jesus the author of Hebrews wrote, “But this Man, after He had offered one sacrifice for sins forever, sat down at the right hand of God” (Hebrews 10:12). His work was complete! By contrasting the sacrifices offered under the Old Covenant with the sacrifice of Jesus, the author of this epistle demonstrates the superiority of the New Covenant (Hebrews 10:11-18). His purpose for writing the epistle was to keep Hebrew Christians from going back to life under the Old Covenant.
When we partake of the Lord’s Supper today, we will not offer Christ again as a sacrifice for sin, but we will remember His one sacrifice of Himself by which He has perfected forever those who are being sanctified.