It is important to see that in Genesis 15, for example, where the promise is made of a temporal people and temporal nation and temporal land, you also have the promise of a far greater reality that transcends it. Not just that God will bring the physical descendants of Abraham back to that land on which he is lying 400 years later (which he did). But that even something greater would happen down the road; namely, that through him and his seed/heir all the families of the earth would be blessed. So you have two promises there in Genesis 15.
That two-fold promise goes all he way through the OT until you do get to the New Testament. In Jeremiah 31 God says that the new covenant will not be like that covenant that Israel swore at Mt. Sinai when it pledged to be God’s holy nation. When the new covenant is inaugurated, it will be the blessing, the greater blessing, that all the families of the earth through Abraham’s greater son. And Jesus Christ is that greater Son.
Photo Credit: ©SWN Design