It was about His Son, Jesus Christ our Lord, who was born as a physical descendant of King David.

They are descended from our forefathers; they are the ones from whom Christ was born physically. He is God over everything [Note: Or this may be "God is over everything"] and should be praised forever! May it be so.

This means that it is not the physical descendants [of Abraham] who are God's children, but it is the children [born] according to [God's] promise who are [Abraham's true] descendants.

For even before the twins were born, and therefore had not done anything good or bad, Rebecca was told [Gen. 25:23], "The older one [i.e., Esau] will serve the younger one [i.e., Jacob]." This was so that God's purpose of choosing and calling [whomever He wanted to] might prevail, instead of [it depending on] what a person did.