Confession of Faith
Chapter 7: Of God’s Covenant with Man
This covenant of grace is frequently set forth in Scripture by the name of a testament, in reference to the death of Jesus Christ the Testator, and to the everlasting inheritance, with all things belonging to it, therein bequeathed.1
Therefore he is the mediator of a new covenant, so that those who are called may receive the promised eternal inheritance, since a death has occurred that redeems them from the transgressions committed under the first covenant. For where a will is involved, the death of the one who made it must be established. For a will takes effect only at death, since it is not in force as long as the one who made it is alive.
This makes Jesus the guarantor of a better covenant.
And likewise the cup after they had eaten, saying, “This cup that is poured out for you is the new covenant in my blood.
1 Corinthians 11:25
In the same way also 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.” (ESV)