 Because of the next statement, you have become her children if you do what is right without being frightened by any fear. He knows that if you're a believer, you're a child of Abraham by faith, right? You remember that, don't you? Very clearly outlined in Romans 4, 11, and 12 in Galatians 3, we are the children of Abraham by faith. And so he's just kind of tagging onto that and saying you not only will be the children of Abraham by faith, but you'll be the children of Sarah, Abraham's wife, by following her.