What does the Bible say about the Holy Spirit's role in salvation?

The Holy Spirit plays a critical role in the process of salvation, which includes the regeneration of those who are spiritually dead. Ephesians 2:1 states that sinners are dead in their trespasses and needs revival, not merely reformation. Titus 3:5 affirms that 'He saved us, not because of deeds done by us in righteousness, but according to His own mercy by the washing of regeneration and renewal in the Holy Spirit.' This indicates that the work of the Spirit is essential for true salvation and is solely an act of God's mercy.