In my book, I argue that Romans 2:17-20 is a compact description of the close relationship between Jewish identity and the synagogue-based communal engagement with the Law of Moses.
I find that there are many fruitful parallels between Romans 2:17-20 and other Jewish texts / authors including the Jewish Scriptures, the Dead Sea Scrolls, Philo, Josephus, 1 Enoch, the Sibylline Oracles, Ben Sira, the Wisdom of Solomon and 4 Baruch.
I conclude that in Rom 2:17-18:
The revelatory value of the Law is not in question for Paul: Paul views Jews as possessors of substantial divine epistemological privileges …
The question, as we shall see in a moment, is not whether the Jewish possession of the Law is a privilege, but rather whether this privilege leads straightforwardly to obedience, as the mainstream Jewish community assumes. (p. 156)
and in Rom 2:19-20:
each of Paul’s descriptions in Rom 2:19–20 alludes, in various ways, to a sense amongst Paul’s Jewish contemporaries that their possession of the Law gave them a special connection to divine revelation, which often implied a divinely ordained role in teaching this revelation to others. (p. 160)
The full details of the argument and further references may be found in chapter 5 of the book (pp. 152-163). The chapter is available from the publisher in electronic format:
Windsor, Lionel J. Paul and the Vocation of Israel: How Paul’s Jewish Identity Informs his Apostolic Ministry, with Special Reference to Romans. BZNW 205. Berlin / Boston: Walter de Gruyter, 2014.