How do we know the necessity of being born again is true?

Jesus' declaration in John 3:3, "Except a man be born again, he cannot see the kingdom of God," serves as a foundational truth in Christian doctrine. The necessity of new birth highlights the transformative work of the Holy Spirit in an individual's life, underscoring that physical lineage or religious observance alone cannot grant one access to the Kingdom of God. This is further confirmed throughout Scripture, where salvation is consistently tied to faith in Christ and the regeneration of the Spirit.