The sign of the old covenant was circumcision. There were other signs and symbols given by God to Israel to designate them as His own, but circumcision was the specific covenant mark. The sign of the new covenant is not baptism, at least it isn’t ever connected as such in the New Testament. While there are some similarities between the two initiating rites, especially that both happen at the beginning and ideally only once, nowhere do we read in the Bible about Christian baptism and a covenant.
We do, however, hear Jesus teaching about the connection between a meal and a covenant. “On the night when he was betrayed” He gave thanks to His Father and gave bread to His men. Then, giving thanks to His Father again, “he took the cup, after supper, saying, ‘This cup is the new covenant in my blood. Do this, as often as you drink it, in remembrance of me.’”
The old covenant was not as good. The author of Hebrews says “Christ has obtained a ministry that is as much more excellent than the old as the covenant he mediates is better, since it is enacted on better promises” (Hebrews 8:6). Then Hebrews quotes Jeremiah 31, leaving in all the parts about “the house of Israel and the house of Judah.”
The blood of Jesus acquired and sealed the new covenant promise. That does not, though, mean that Jesus’ blood finished the covenant. Obviously it didn’t. His word guaranteed it, His blood obtained it, and His Spirit will complete it.
So there is both an already and a not yet as well as an in addition. Those of the household of Israel who believed in the first century and centuries since are evidence of the beginning of what still will be finished, atonement and restoration. Gentiles also who believed in Paul’s day and in ours are evidence of God’s grace to extend salvation to the nations. This meal is a long session in the same direction.
When Jesus instituted the Supper of remembrance He told His disciples, “this cup that is poured out for you is the new covenant in my blood” (Luke 22:20). What was the new covenant and how is the Lord’s Table connected with it?
The New Covenant was God’s promise to “the house of Israel and the house of Judah” (Jeremiah 31:31; Ezekiel 36:22, 32) to do for them what they failed to do in the previous covenant. Ezekiel described how God would give them a new heart (Ezekiel 36:26), which they could not do for themselves. Jeremiah described it differently. He wrote that God would put His law into them, He would write it on their hearts (Jeremiah 31:33a). The prophecy goes further.
I will be their God, and they shall be my people. And no longer shall each one teach his neighbor and each his brother, saying, ‘Know the LORD,’ for they shall all know me, from the least of them to the greatest, declares the LORD. For I will forgive their iniquity, and I will remember their sin no more. (Jeremiah 31:33b–34, quoted in Hebrews 8:8-12)
God makes a promise to make Himself known. In light of what knowing God means in John 17:3, God makes a covenant to give eternal life.
The New Covenant belongs to the nation of Israel. The sun will stop and the heavens will be measured before that changes (see verses 35-37). But God gives life through the knowledge of Himself to all His people, including the “children of God scattered abroad” (John 12:52). God is gathering His people from every tribe, tongue, and nation with a special fulfillment still to come among Israel. This is His own covenant at His own cost because it is His own character. He is making Himself known.
Jesus’ death on the cross not only purchased our forgiveness, it is part of knowing Him. In his book Delighting in the Trinity, Michael Reeves wrote, “On the cross, Christ the Glory puts to death all false ideas of God.” He makes Himself known so that we can have life and our life brings Him glory as the life-giver. This meal of remembrance that Jesus instituted is our life because here we know God and here we glorify God.