
A New Covenant
We have distinguished three kinds of covenants: (1) negotiated agreements, (2) unconditional promises, and (3) law with promise and penalty. The new covenant mediated by Jesus Christ is of the 3rd kind.
The old law of Moses was this kind of covenant. God said, "Now then, if you will indeed obey my voice and keep my covenant, then you shall be my own possession among all the peoples, for all the earth is mine; and you shall be to me a kingdom of priests and a holy nation..." (Exo 19:5-6).
Moses pleaded with the children of Israel to "enter in to the covenant with the Lord your God and into his oath which the Lord your God is making with you today" (Deu 29:9-10,1:8, Deu 30:15-20).
This covenant, however, existed whether or not the people entered into it. They had a relationship with God, dictated by that covenant —whether they liked it or not. If they entered into the covenant they were friends with God. If they rebelled against the covenant, they were enemies of God. Either way, they had a “covenant relationship” with God.
The new covenant is also of the third kind. Jesus "has obtained a more excellent ministry, because he is the mediator of a better covenant, which is based on better promises" (Heb 8:6-8). So the new covenant is vastly different from the old. It is not, however, different as to type. Although a far better covenant, it was still instituted by God unilaterally as a law with promise and penalty.
How many times did Jesus say, "keep my commandments... keep my words..." (eg Jhn 8:51-52,1:8, Jhn 14:15,23). The new covenant is a covenant of magnificent promises to those who keep its commandments. For those who don't, it has dire warnings.
The new covenant mediated by Christ is therefore likened to a person's last will and testament granting an inheritance (Heb 9:15-17). God has written his will so that anyone can become heirs of God. His will promises certain blessings, stipulates certain conditions, and decrees the penalty for non-compliance.
To summarize: God did not negotiate the new covenant with human beings. He mediated it to them through the appointed High Priest Jesus who offered himself as the necessary sacrifice. So, through the authority of Jesus, every person has a “covenant relationship” with God. Everybody is subject to the new covenant. This is a law covenant, because it is conditional, with either of two outcomes for each person —namely grace or wrath. Which of those alternatives is the outcome for any individual, depends on whether that person obeys or disobeys the terms or commandments of the covenant.
That is how the new covenant was instituted.