But what does the Scripture say? “Throw out the slave woman and her son. The son of the slave woman should not inherit anything. The son of the free woman should receive it all.”
God chose the Israelites to be his people before they were born, and he has not thrown his people out. Surely you know what the Scripture says about Elijah, how he prayed to God against the people of Israel.
Instead, the Scriptures showed that the whole world is bound by sin. This was so the promise would be given through faith to people who believe in Jesus Christ.
The Scriptures, telling what would happen in the future, said that God would make the non-Jewish people right through their faith. This Good News was told to Abraham beforehand, as the Scripture says: “All nations will be blessed through you.”