And here is an explanation.
Note that both of these quotes refer to the HOUSE of Israel and the HOUSE of Judah.
What,
or who, is the house of Israel and the house of Judah?
I think the answer is the king.
In
2Sam 12:8 the Lord (via Nathan) says to David
"I..... gave you the house of Israel and of Judah..."
The king represents
in himself the house of Israel and the house of Judah.
Another example of the king personifying the whole house is given in Isaiah 7:13 where Isaiah calls king Ahaz the house of David.
Now who became the King?
Who was promised the throne of David?
Answer: Jesus:
"He will be great, and will be called the Son of the Most High;
and the Lord God will give to him the throne of his father David,
and he will reign over the house of Jacob for ever;
and of his kingdom there will be no end.” (Lk 1:32-33).
Jesus
is the New Covenant promised in Jeremiah; he embodies the Covenant in himself.
In Isaiah, God speaks about the coming Messiah in several "Servant" passages
Is 42:6-7 I have given you as a covenant to the people, a light to the nations, to open the eyes that are blind, to bring out the prisoners from the dungeon, from the prison those who sit in darkness. This is very similar to what Jesus says about himself in
Lk 4:18
Is 49:8 I have kept you and given you as a covenant to the people,
The implications are that
Jesus is a living embodiment of the Covenant
The Messiah is given as a Covenant to the people, an embodiment of the covenant.
And note he is to be a "light to the nations". He is not just for the Jews.
3. The Mosaic/Sinai Covenant could be, and was, broken. But if Jesus is the embodiment of the Covenant it can never be broken. That is why it is an everlasting covenant .
God says to Ezekial (and note this is long after David is dead)
“My servant David shall be king over them; and they shall all have one shepherd. They shall follow my ordinances and be careful to observe my statutes. They shall dwell in the land where your fathers dwelt that I gave to my servant Jacob; they and their children and their children’s children shall dwell there for ever; and David my servant shall be their prince for ever. I will make a covenant of peace with them; it shall be an everlasting covenant with them (Ez 37:24-26).
Anyone can come into this Covenant. Since the Covenant is Christ, if we are "in Christ", a phrase Paul used often, we are in the Covenant.