Question: "What did Jesus mean when He said, "This cup is the new covenant in my blood"?"
Answer: At the Last Supper, Jesus took a cup and said, “This cup is the new covenant in my blood, which is poured out for you” (Luke 22:20). Moments before, the Lord had broken the bread and given it to His disciples with the words, “This is my body given for you; do this in remembrance of me” (verse 19). With these symbolic actions Jesus instituted the ordinance of communion, or the Lord’s Table.
The “new covenant” that Jesus spoke of is in contrast to the Old Covenant, the conditional agreement that God had made with the Israelites through Moses. The Old Covenant established laws and ceremonies that separated the Jews from the other nations, defined sin, and showcased God’s provision of forgiveness through sacrifice. The New Covenant was predicted in Jeremiah 31:31–33.
The Old Covenant required blood sacrifices, but it could not provide a final sacrifice for sin. The Old Covenant required repeated, daily sacrifices of animals as a reminder of the people’s sin. But, as Scripture says, “it is impossible for the blood of bulls and goats to take away sins” (Hebrews 10:4). Under the Old Covenant, the same inadequate sacrifices were constantly repeated. For every sin, the process was replicated, day after day, month after month, year after year. The Old Covenant never provided a full, complete sacrifice for sin. “For if that first covenant had been faultless, there would have been no occasion to look for a second” (Hebrews 8:7, ESV).
Jesus came to establish a “better covenant” (Hebrews 7:22), a “new covenant” that Jesus said was in His blood. Jesus shed His blood on the cross to take away the sins of the world (John 1:29) and ratify the new covenant between God and man. On the night He was betrayed, Jesus took the cup and said to His disciples, “Drink from it, all of you. This is my blood of the covenant, which is poured out for many for the forgiveness of sins” (Matthew 26:27–28). By “this cup,” Jesus referred, by metonymy, to the contents of the cup, which was the “fruit of the vine” (Mark 14:25). This was representative of Christ’s blood. Jesus gave His disciples the cup, infusing it with new meaning, and told them drinking it was to be a memorial of His death: it was to be drunk “in remembrance of me” (1 Corinthians 11:25). Now, “whenever you eat this bread and drink this cup, you proclaim the Lord’s death until he comes” (verse 26).
The New Covenant is based on faith in the shed blood of Christ to take away sin, not on repeated sacrifices or any other kind of work (see Ephesians 2:8–9). Because Jesus is the holy Lamb of God, His one-time sacrifice is sufficient to atone for the sins of all who believe in Him. We “partake” of Jesus by coming to Him in faith (John 1:12), trusting that His shed blood (and broken body) is sufficient to pay for our sins. The elements of bread and wine commemorate His death and the shedding of His blood. When we eat those elements in communion with other believers, we affirm our faith and fellowship in Christ.