I have to mention Ezra from our first reading, being the canon lawyer that I am. Because, you see, Ezra is connected to the law and quite significant when it comes to establishing the foundation for church law.
Ezra lives about 450 BC during the Diaspora, or when the Jews were dispersed throughout the Middle East. Jerusalem had been destroyed and many of the Jews taken into captivity in Babylon. He is a scribe and priest (remember how Jesus confronts the scribes?). He is sent by Artaxerxes, the King of Persia, who has conquered the area, back to Jerusalem to reestablish the Torah or the law to the Jews who were now living back in Israel.
Ezra was commissioned for this project because he was a man of the law. He had introduced to Jewish communities living outside of Israel to the customs of the faith. These weren't just haphazard practices created by Ezra, but practices outlined in the law. Following the law, therefore, connected these scattered Jewish peoples to the true faith. They couldn't physically worship in Jerusalem. But this didn't mean they still couldn't be Hebrews. If they followed the law, their identity was established. So, it wasn't political nationality, ethnic background, or even regular participation in the Jerusalem temple cult, but following the law that made them God's chosen people.