Romans 3:1 What advantage, then, is there in being a Jew, or what value is there in circumcision? 2 Much every way: chiefly, because that unto them were committed the oracles of God.
Your proof text is inappropriate, as you missed the entire second chapter.
God transmitted His law to the Jews. They thought if they had the outward appearance of the law, circumcision, then that was enough. The second chapter closes with the admonition that one must be circumcised of heart.
As we enter the 3rd chapter, the discussion continues. Just because one hears the law, doesn’t mean a thing. One has to act according to it, in the spirit of it.