How is the kingdom of God established in believers' hearts?

The kingdom of God is established in believers' hearts through the transformative work of the Holy Spirit, which is necessitated by the new birth as articulated in John 3:3-7. This spiritual regeneration allows individuals to understand and experience the kingdom that is not of this world. When a person is drawn to Christ and seeks the kingdom earnestly, their heart is changed, aligning with God's values and purposes. The kingdom's establishment is contingent upon an individual's surrender to Christ and His reigning authority within their life.