Why do we dwell on the root and fatness of Abraham?
We dwell on the root and fatness of Abraham because the promises God made to Abraham now become ours. After Israel slips off the scene, Gentiles enter that place, so we enter into the whole concept of being joint heirs according to the promises.
Les explains that God made the promises to Abraham around 2000 B.C., and out of him would come the nation of Israel. Through Israel would come the Law, and Israel would be the vehicle that crucified the Redeemer and made our salvation possible. But then Israel slips off the scene, and the Gentiles come into that place. Therefore we dwell on the root and the fatness of Abraham, because all of those promises made to Abraham now become ours. That brings us into the concept of being joint heirs according to the promises, which points back to Romans chapter 8. There, as many as are led by the Spirit of God are the sons of God, not hoping to be or might be, but they are the sons of God. Believers have not received the spirit of bondage again to fear; the Law was a burden and severe, and Israel lived in a segment of fear.