How do we know regeneration is a work of the Holy Spirit?

Regeneration, or being born again, is a vital doctrinal truth in Reformed theology, illustrated in Titus 3:5 where it references the washing of regeneration and renewing of the Holy Spirit. This regeneration is essential for salvation and signifies a transformative act where the Holy Spirit intervenes in the lives of the elect. It is not a result of human works but a demonstration of God's mercy and grace. This divine act is critical as it prepares the heart to respond to the gospel and embrace faith in Jesus Christ. In historic Reformed thought, regeneration is seen as the precursor to faith and an essential part of the new birth experience.