Galatians 4:23, 29

The son of the slave wife was born in a human attempt to bring about the fulfillment of God’s promise. But the son of the freeborn wife was born as God’s own fulfillment of his promise.

But you are now being persecuted by those who want you to keep the law, just as Ishmael, the child born by human effort, persecuted Isaac, the child born by the power of the Spirit.