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.
Abraham and Lot displayed the act of loving their neighbor and loving the stranger among them. Obedience to this command has reaped blessings many times. These cases with Abraham and Lot are almost identical to what happened with the disciples after the resurrection of Messiah (Luke 24:28-31).
Torah states that all men must be circumcised before they partake of Passover (Exodus 12:48-49). Torah is very specific in that all eight day old baby boys and all men who wish to participate in Passover are to be circumcised.