Christ's blood that ratifies the new covenant promised in Jeremiah 31:31-34. At the Last Supper, Christ takes the cup and names it: this is my blood of the new testament, which is shed for many for the remission of sins (Matt 26:28; Luke 22:20). The image echoes Moses sprinkling sacrificial blood on the people to seal Sinai's covenant (Ex 24:8) — the same pattern, now fulfilled and surpassed in the blood of the Mediator (Heb 9:14-15). Where the old covenant required repeated animal sacrifices that could never finally take away sin, Christ's once-for-all blood-shedding eternally seals the new (Heb 10:10-14). To drink the cup of communion is to participate in this very ratification — not symbolically only, but in living covenantal union with the One whose blood was spilled.