Abraham symbolizes two aspects of the integral trajectory in the Biblical Narrative. The first aspect relates to his grandson Jacob who later became Israel. This aspect is biological through genealogy and lineage. The second aspect relates to Abraham's son Isaac. Paul notes that ultimately Abraham's descendants would be through his seed singular - meaning Christ. The birth of Isaac and the resurrection of Christ both come by the power of God. Paul is setting the stage for correcting the gentile misunderstanding about salvation and their saved/lost paradigm.
