Galatians 4:23

4:23 But one, the son by the slave woman, was born by natural descent, while the other, the son by the free woman, was born through the promise.

Galatians 4:28-29

4:28 But you, brothers and sisters, are children of the promise like Isaac. 4:29 But just as at that time the one born by natural descent persecuted the one born according to the Spirit, so it is now.