King James Bible
"That which is born of the flesh is flesh; and that which is born of the Spirit is spirit."
Jesus establishes that natural human birth produces only natural humanity—limited, fallen, and unable to transcend its earthly nature. This responds to Nicodemus's confusion about physical rebirth, clarifying that human effort or lineage cannot produce spiritual transformation. Spiritual birth comes exclusively through the Holy Spirit's work, creating a fundamentally different kind of life that participates in God's own nature. This parallel structure emphasizes the absolute distinction between two realms of existence, explaining why entering God's kingdom requires supernatural regeneration rather than human achievement.