In this imaginary dialogue with “Judaism,” one question remains: What, then, was the purpose of circumcision and the law of Moses? Was it all in vain? Not at all, Paul seems to respond. It is precisely the “law of faith” now revealed in the person of Jesus, who died and rose again, that is the key that interprets and validates the “law of Moses” and circumcision.
The Apostle, with Scripture in hand, continues to demonstrate this by going back to Abraham, the key figure of the Jewish people. He emphasizes the most important moment in the Patriarch’s life: God promises him, in his old age, descendants as numerous as the stars in the sky. Despite all human hope, the Patriarch trusted God: “he believed the Lord, and the Lord counted it to him as righteousness” (Gn 15:6), meaning he accepted faith freely, was justified, and received salvation.