God's covenant of grace is one huge covenant. It lasts from Genesis 3 and the fall of mankind to the very end of history, but it unfolds progressively in stages. When we come to Abraham, and then followed by Moses and David, you have this covenant of promise with Abraham, the covenant of the law with Moses, and the covenant of the kingdom with David, God is kind of narrowing down his covenantal focus to a specific people, Israel, the Jews, the Hebrews… And so, he's forming this covenant more and more around this people, stronger and stronger to kind of hedge these people in so that they are not defiled by the nations around them, by their idolatry and immorality and wicked ways. That's why these prophets come along, and they speak very forcefully about the way Israel has been polluted by these things. They're not just concerned about the spiritual welfare of the Old Testament people; they're concerned about the Christ who will be born… So, this covenant of grace focuses down on this people of Israel for the sake of Jesus Christ, and then after he has died and risen from the grave, this covenant opens up again into the new covenant and expands to the ends of the earth. So, you kind of see this broad covenant with Adam and Noah, narrowing down to the phases of the covenant with Abraham and Moses and David, and then opening up again, almost like an hourglass, to take in the nations of the world. And that's why they're very nationalistic. They're rooted in Hebrew life and laws. They're rooted in the temple. They're dependent upon the kingship of David in particular because this is the time in which God is creating a special incubator into which will be born … Jesus Christ, for the sake of the whole world eventually.