And note that Abraham is called by Paul, the "father of us all." The emphasis in that title is on what Abraham received through faith - righteousness - because he believed God's promise, not on what he did in works of obedience: "That is why it depends on faith, in order that the promise may rest on grace and be guaranteed to all his offspring—not only to the adherent of the law but also to the one who shares the faith of Abraham, who is the father of us all, as it is written, “I have made you the father of many nations”—in the presence of the God in whom he believed, who gives life to the dead and calls into existence the things that do not exist" (Rom 4:16-17).
Is this to say that we don't need the Ten Commandments or need not attend to the Law as the rule of righteousness and obedience informing us of the will of God? Not at all. The written law is a great help to better inform us as to God's holiness and our obedience as those created in the moral image of God. But I think the above does speak to the priority and ground of justification - the righteousness that comes through faith - when considering what empowers our obedience in sanctification; as well as the gospel truth that the moral law has been written afresh on the new heart and will of the justified sinner.
But this is the covenant that I will make with the house of Israel after those days, saith Jehovah: I will put my law in their inward parts, and in their heart will I write it; and I will be their God, and they shall be my people (Jer. 31: 33).
For I delight in the law of God after the inward man (Rom 7: 22).