(Galatians 4:28-31 KJV) Now we, brethren, as Isaac was, are the children of promise. But as then he that was born after the flesh persecuted him that was born after the Spirit, even so it is now. Nevertheless what saith the scripture? Cast out the bondwoman and her son: for the son of the bondwoman shall not be heir with the son of the freewoman. So then, brethren, we are not children of the bondwoman, but of the free.
(Galatians 4:28-31 AMP) But we, brethren, are children [not by physical descent, as was Ishmael, but] like Isaac, born in virtue of promise. Yet [just] as at that time the child [of ordinary birth] born according to the flesh despised and persecuted him [who was born remarkably] according to [the promise and the working of] the [Holy] Spirit, so it is now also. [Gen. 21:9.] But what does the Scripture say? Cast out and send away the slave woman and her son, for never shall the son of the slave woman be heir and share the inheritance with the son of the free woman. [Gen. 21:10.] So, brethren, we [who are born again] are not children of a slave woman [the natural], but of the free [the supernatural].
Each one of us was conceived by physical conception and we entered this world through natural birth. But the day that you got born again you were conceived through spiritual conception and there was a spiritual birth that took place which renewed your spirit man and transformed it, to no longer function according to the flesh but according to the spirit. Verse 31 says… that we are no longer children of the bond woman or of the natural, but we are children of the free... Which actually means that we are children of the supernatural. This means that God took our natural man and he slapped his super onto our natural and we all got born again as supernatural beings that have a direct access to a supernatural God!
Supernatural = exceeding the powers or laws of nature. It's when the natural events of mankind are interrupted by a divine intervention.