The whole tenor of the writing takes a shift just before that verse. Paul is now showing that Jews and Gentiles are ALL in the same boat:
Indeed ...Romans 3:9 What shall we conclude then? Are we any better? Not at all! We have already made the charge that Jews and Gentiles alike are all under sin.
10 As it is written: "There is no one righteous, not even one;
11 there is no one who understands, no one who seeks God.
12 All have turned away, they have together become worthless; there is no one who does good, not even one."
...
28 For we maintain that a man is justified by faith apart from observing the law.
29 Is God the God of Jews only? Is he not the God of Gentiles too? Yes, of Gentiles too,
30 since there is only one God, who will justify the circumcised by faith and the uncircumcised through that same faith.
31 Do we, then, nullify the law by this faith? Not at all! Rather, we uphold the law.
bttt