Galatians 4:23-24

23Hagar was a slave. Her son was born as a result of what Abraham himself decided. But Abraham's wife, Sarah, gave birth to the other son. That son was born as a result of what God had promised to Abraham.

24These two women are like pictures of two agreements that God made with his people. Hagar is like the agreement that God made on Sinai mountain. That agreement causes people to become slaves.