What does Romans 9:9 mean?
Paul is pulling examples from Israel's history to show what distinguished a "true" Israelite from one who is merely born into the nation. He wants to show, in the end, that God will keep His promises to Israel through those who are truly children of the promise. Mere biology is not the key; what ultimately matters is whether or not a person has the right relationship with God. Paul will use this line of thought to explain why Gentiles, and not only Jews, can be part of God's plan of salvation.He points here to one of the promises given by God to Abraham. After many years of promising that Abraham and Sarah would have a son, God now promises that Sarah will give birth in one year's time (Genesis 17:21; 18:10, 14). Only that child, Isaac, was the child of a promise. Abraham's other children, born before and after Isaac, were not born as the result of a promise of God.