Galatians 4:26-31

But the heavenly Jerusalem, which is above, is like the free woman. She is our mother. It is written in the Scriptures: “Be happy, Jerusalem. You are like a woman who never gave birth to children. Start singing and shout for joy. You never felt the pain of giving birth, but you will have more children than the woman who has a husband.” My brothers and sisters, you are God’s children because of his promise, as Isaac was then. The son who was born in the normal way treated the other son badly. It is the same today. 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.” So, my brothers and sisters, we are not children of the slave woman, but of the free woman.