God makes a covenant of peace; an everlasting covenant

Ezekiel 37:15-28
This is what the Sovereign Lord says: I will take the Israelites out of the nations where they have gone. I will gather them from all around and bring them back into their own land. I will make them one nation in the land, on the mountains of Israel. There will be one king over all of them and they will never again be two nations or be divided into two kingdoms. They will no longer defile themselves with their idols and vile images or with any of their offenses, for I will save them from all their sinful backsliding, and I will cleanse them. They will be my people, and I will be their God.
I will make a covenant of peace with them; it will be an everlasting covenant. I will establish them and increase their numbers, and I will put my sanctuary among them forever. 
The two warring kingdoms will become one nation under one king - a new David. And here the promise to the exiles merges into the full blessing of the future golden age. The return is only a foretaste(預示) of all God has in store for his people.
Why?
Two nations will be one nation, so Israel and Judah divided is not the mind of the Lord, God let them divided and God will make them be united under one king - the new David, Jesus Christ.
God chose his people and be their God, like shepherd to sheep.
There is an everlasting covenant among God and his people, there is God's sanctuary among them forever. This kingdom has existing over 2018 years.
How?
God makes a everlasting covenant with us, this is a peace covenant. Praise to the Lord and follow his decrees and command. LORD, you alone are my portion and my cup; you make my lot secure. (Psalm 16:5)