This is a familiar expression for Paul (2 Cor. 11:31, Gal. 1:20). He is emphatic in what he knows to be true. This section of Romans doesn’t deal as much with the beautiful, lofty, and comforting doctrine of obedience to Torah that was dealt with in the previous chapters. Paul left chapter 8 telling us that absolutely nothing can separate us from the love of Messiah Yeshua. It seems now that Paul is going to fall into a deep depression. I think he does, to an extent. Paul is now going to discuss the sadness he has over the fact that most “Israelites according to the flesh” (his words) rejected the New Covenant offered to them through Yeshua Messiah.
Christianity has struggled with the answer to this passage. Is Yeshua saying the opposite of what He has been saying all along? Is He now saying to obey what the Pharisees say and follow their traditions even though their actions are wrong? One good answer is to look in the Shem Tov.