God makes a deal with Adam: you keep gardening, and I will live with you forever. Adam screws up his part of the deal. But then God makes a strange promise: one day, Eve will have a son who will redeem everything.

God makes a deal with Noah: you build me a boat, and I will make an eternal covenant of salvation with you. Noah keeps his part of the deal. Could this be Eve’s Son, the long-awaited Messiah?
Nope.

God makes a deal with Abraham: you build me a family, and I will 1. turn you into a great nation. 2. give your great nation a homeland. 3. make sure Eve’s Son is descended from you. Abraham keeps his part of the deal. So God fulfills part 1 of his covenant: he turns Abraham into a great nation.

God makes a deal with Moses: you build me a holy nation, and I will keep part 2 of my covenant with Abraham, I will give your great nation a homeland. Moses keeps his part of the deal. So God keeps his part of the deal. Then they live happily ever after?
Nope.

God makes a deal with David: you build me a holy kingdom, and I will confirm part 3 of my covenant with Abraham, I will finally give you Eve’s Son, the Messiah you have been waiting for. David keeps his part of the deal. So God promises to keep his part of the deal — but not quite yet.

God the Father makes a deal with his Son: you redeem the earth like Adam was supposed to do, and through you I will fulfill all my previous eternal covenants with Noah, Abraham, Moses, and David. The Son keeps his part of the deal. So the Father keeps his.