What did the covenants with David and Moses concern?
The covenant God made with David concerned the royal family, while the covenant He made with Moses concerned the land of Palestine. Both were separate covenants, yet they operated under the overarching Abrahamic covenant, which promised a nation, a land, and a coming King-Redeemer.
Les explains that after the Abrahamic covenant, God made the covenant of law, then the covenant with David concerning the royal family, and the covenant with Moses concerning the land of Palestine. These were all separate covenants, but they were all under the Abrahamic covenant. The Abrahamic covenant promised a nation of people, a geographical area of land, and that at some future time God would come and be their King and Redeemer. Israel had been a nation for 1,500 years, had been in and out of the land, and after Babylon they were back, setting the stage for John the Baptist's message.