For it is written that Abraham had two sons; one of the maid servant, and one of the free woman.

But he that was of the maid servant was born according to flesh, and he that was of the free woman through the promise.

But what says the scripture? Cast out the maid servant and her son; for the son of the maid servant shall not inherit with the son of the free woman.

So then, brethren, we are not maid servant's children, but children of the free woman.