What does Romans 9:31 mean?

Paul is using a question-and-answer approach to sum up what he has written in this chapter. In fact, he's tying together concepts used throughout the book of Romans. He imagines an incredulous Jewish person asking the question posed in the previous verse and in this one. That person might have asked, "are you saying, Paul, that even though the Gentiles never pursued the righteousness of God by attempting to follow the law of Moses, that those who have faith in Christ have been given God's righteousness, anyway? Are you also saying, Paul, that Israel, who has pursued God's righteousness by attempting to live under the law for generations, has not succeeded in keeping the law and has not been declared righteous by God?"

Paul's answer to both questions is a simple "yes." He has taught throughout this book that being declared righteous before God comes only through faith in Christ. That status cannot be reached by following the law. In the following verse he will answer the next question: Why?