Galatians 4:29-31

But as then he that was born after the flesh persecuted him that was born after the Spirit, so also it is now. Howbeit what saith the scripture? Cast out the handmaid and her son: for the son of the handmaid shall not inherit with the son of the freewoman. Wherefore, brethren, we are not children of a handmaid, but of the freewoman.