What was the third promise of the Abrahamic covenant?
The third promise was that God Himself would come as their King and Messiah, also their Redeemer and Savior. Having become a nation in a geographical land, Israel would need a government; therefore the promised Messiah would reign over them, bringing salvation as well.
Les teaches that the Abrahamic covenant basically contained three promises, and all the other covenants are wrapped up inside it. The first promise was that out of Abraham would come a nation of people, Israel. The second was that as a nation they would be placed in their own geographical area of land, the promised land. The third promise was government: since people in a geographical area must have a government, God Himself would come in the person of the Messiah to be their King, Messiah, Redeemer, and Savior. Les also emphasizes that a viable kingdom cannot exist without a king, and a king is of no earthly use without a kingdom. When Jesus came and John the Baptist presented Him as Israel's King, the kingdom was in the long view.