How do we know being born again is necessary for salvation?

Being born again is a foundational doctrine in the Christian faith, emphasized by Jesus in John 3:3 when He tells Nicodemus that one must be born again to see the kingdom of God. This spiritual rebirth indicates transformation and renewal of the heart, making the individual a new creation in Christ. Without this rebirth, individuals remain dead in their sins and separated from God. The necessity of new birth is affirmed throughout the New Testament, underscoring that such regeneration is a work of the Holy Spirit, enabling believers to have a genuine relationship with God and live according to His will.