How do we know that the sacrifice of Christ is a New Covenant?

The New Covenant is rooted in the Old Testament but brought to fulfillment in Christ. In Luke 22:20, Jesus declares that the cup represents the new covenant in His blood, which is shed for many. This indicates that Christ's sacrificial death not only redeems but also establishes a new relationship between God and His people. Hebrews 9:15 further elaborates on this by stating that through His death, Christ mediates a new covenant that offers eternal redemption, signifying a shift from the old sacrificial system to the complete and sufficient sacrifice made once for all by Jesus Himself.