People who are born again are a new creation in Christ. Christians have been given new life in Christ. They have a new nature in them after they come to faith in Christ. To Paul, this is more significant than a person's ancestry. (See: [[rc://en/tw/dict/bible/kt/bornagain]] and [[rc://en/tw/dict/bible/kt/faith]])
This is a complex issue. "Flesh" is contrasted with "spirit." In this chapter, flesh is also used to refer to the physical body. (See: [[rc://en/tw/dict/bible/kt/flesh]] and [[rc://en/tw/dict/bible/kt/sin]] and [[rc://en/tw/dict/bible/kt/spirit]])