Are you a true Jew? Do you want to be? Should you be?
The first Jews were given every privilege and opportunity by God and yet it seemed to make no difference to them. Paul writes to tell them that they too are sinners who need a saviour and that the gospel is for them as much as it is for the Gentiles. Having and knowing so much, they still missed the point and failed to do with it as they should.
The true Jew is one saved by grace alone through faith alone. They are those whose hearts have been changed and are inclined in their love, affections and obedience towards God.