How do we know that we must be born again?

Being born again is a foundational doctrine in Christianity, as articulated by Jesus in John 3:3, 'Unless one is born again, he cannot see the kingdom of God.' This highlights the profound spiritual transformation required for true faith and understanding. By nature, we are all descendants of Adam, marked by sin and corruption (Romans 5:12). It is only through the regenerating work of the Holy Spirit that we can recognize our sinfulness and turn to Christ for salvation. Thus, without this new birth, we remain spiritually blind to the truths of the gospel and our own need for redemption.