Romans 9:11-15, 18, 21

And before her twin sons were born, God spoke to Rebekah and said: “The oldest will serve the youngest.” God spoke these words before the sons had done anything good or bad, which proves that God calls people not on the basis of their good or bad works, but according to his divine purpose. For in the words of Scripture: “Jacob I have chosen, but Esau I have rejected.” So, what does all this mean? Are we saying that God is unfair? Of course not! He had every right to say to Moses

So again we see that it is entirely up to God to show mercy or to harden the hearts of whomever he chooses.

Or are you denying the right of the potter to make out of clay whatever he wants? Doesn’t the potter have the right to make from the same lump of clay an elegant vase or an ordinary pot?