Romans 9 is Paul’s review of Jewish history, and is too often misunderstood because it is not read as being of a piece with Paul’s experience of his own Jewishness. His people are a chosen people, and his heart is broken at their cavalier recklessness and presumption regarding their favored status. He could wish himself accursed for the sake of his people (9:3). All the benefits of being God’s chosen people - God’s adopted children, no less - the covenants, the temple, and the promises were their’s for the taking, but they despised their birthright, and forfeited many of the blessings of being chosen. It was not God who broke His promise, but the children who blocked the fulfillment of the promises in their experience. As it turned out it was those who sought the God who made the promises who were reckoned as His chosen children (9:8). This is evident in the inclusion in the Messianic line of several people who were not descendants of Abraham. These people were welcomed into the family of the chosen on the strength of their choice to cast their lot in with the Israelites. Their inclusion is not based on the merits of their choice though their choices are pivotal, but on the merits of God’s promise.
Abraham had two sons, but not all of the sons are included as the children of Israel (9:6). Abraham messed that up with his machinations intended to help God fulfill His promise. When that caused familial squabbles Abraham had to send Ishmael and his mother away. Hence God is reduced to giving Abraham children as numerous as the stars in the heavens, or the sand on the seashore, through one solitary son, but God does not give up on His own promise. He told Abraham he would be blessed and He will bless Abraham, and the world through his family.
Both of Isaac’s children turn out to be shysters and hooligans. The younger brother cheats the elder out of his birthright and the blessing, and the elder bother vows to kill the younger for his shenanigans. The younger brother flees for his life and trades cheats with his uncle for 14 years. There is still no meritorious material for making a family who will be a channel of blessing for the world, but still, God does not give up. He will bless the world through Abraham, and since there is no obvious candidate based on honorable conduct, God chooses the younger to emphasize that his blessing falls undeserving on all who will submit to His blessing. God’s purpose in choosing the Israelites as a vessel of blessing for the world will stand, even though He must repeatedly covenant to do so through reluctant vessels (9:11f in order that God's purpose in election might stand: not by works but by him who calls).
Throughout the rest of the chapter Paul emphasizes that God’s choices are always in our favor.
“I will have mercy on whom I have mercy, and I will have compassion on whom I have compassion.” (9:15) “I will call them ‘my people’ who are not my people; and I will call her ‘my loved one’ who is not my loved one” and “It will happen that in the very place where it was said to them, ‘You are not my people,’ they will be called ‘sons of the living God.’” (9:25, 26)
God’s choices are not to bless some and damn others. God’s choices are always to have mercy and compassion, even when there is no justification for such. God’s choices are always to include as many as will heed His call among those whom He calls His chosen people. God’s choices are always good news for all people. Left to our own ways we would quickly bring on ourselves the destruction of Sodom and Gomorrah (9:29), but because God chooses otherwise we have the opportunity to make choices we do not deserve to have, and we are inundated with blessings we do not merit. When we would justly be the objects of His wrath He is patient and continues to call (9:22-24). Thanks be to God!!
God gave Pharaoh an opportunity to be part of his redemption plan for His children (9:17). Pharaoh chose to work against God’s purposes and suffered for it, but God continued to work out his plan for the redemption of His children. Pharaoh would not be unchanged in this experience. He would come out the other side of this experience a changed man, battle hardened, but whether that hardening would be for good or evil would depend in large measure on how he chose to respond to the opportunity God sent his way.
Paul continues with quotes from the prophets in which God warns His chosen children that their ways constantly lead them to ruin, but he also tells them that He will, because of His grace and mercy, institute remedies far beyond what their imagination could conjure in order to work salvation for them. Those who seek a salvation which they control will not find it. Those who go about their life not worrying about their salvation will realize a salvation that only God could provide.