Romans 9 is awesome.

The first part is about the 3 different kinds of seed. Then the complaint is issued why doesn't God provide salvation through the whole line of Abraham and Isaac? He says its not fair. God says what He is doing is perfect. Then we see the spiritual seed which is also given to the Gentiles whoever places their trust in the Cornerstone.

I can't remember who said it, but the Bible was written a long time ago, meaning, they are often referencing the Jews and how they have forsaken the Lord. Be careful how you read. This being Calvinists favorite chapter, my advice would be, take the lens of Calvinism off and read as it is intended.

The Calvinist will say the clay is not Israel but Jeremiah says it is: [Jer 18:5-12 NLT] 4 But the jar he was making did not turn out as he had hoped, so he crushed it into a lump of clay again and started over. 5 Then the LORD gave me this message: 6 "O Israel, can I not do to you as this potter has done to his clay? As the clay is in the potter's hand, so are you in my hand. 7 If I announce that a certain nation or kingdom is to be uprooted, torn down, and destroyed, 8 but then that nation renounces its evil ways, I will not destroy it as I had planned. 9 And if I announce that I will plant and build up a certain nation or kingdom, 10 but then that nation turns to evil and refuses to obey me, I will not bless it as I said I would. 11 "Therefore, Jeremiah, go and warn all Judah and Jerusalem. Say to them, 'This is what the LORD says: I am planning disaster for you instead of good. So turn from your evil ways, each of you, and do what is right.'" 12 But the people replied, "Don't waste your breath. We will continue to live as we want to, stubbornly following our own evil desires."

So God breaks a chunk of clay off the original clay in Romans 9. These are the Jews with the Noble Cause of the gospel of salvation.