What advantage then hath the Jew? or what profit [is there] of circumcision?
Note 1 at Ro 3:1: Paul had just proven that the Jews were as guilty as the pagans whom they disdained (see note 1 at Ro 2:1). This led to the question, "What advantage is there in being a Jew?" Paul gave the most important answer to that question in Ro 3:2 (see note 2 at that verse) and then addressed the issue more in Ro 9:4-5.