Why must we be born again to enter the Kingdom of Heaven?

Jesus teaches in John 3 that we must be born again to enter the Kingdom of Heaven. This new birth is a sovereign act of God where He imparts spiritual life to those dead in their sins, just as Levites were born into their lineage without any choice of their own. Just as one cannot become a Levite through effort or decision, individuals cannot enter the Kingdom through works or traditions. Rather, it is through God's grace and the regenerating work of the Holy Spirit that we are made alive to faith and repentance, allowing us to inherit eternal life.