Why is regeneration necessary for salvation in Reformed theology?

In Reformed theology, the necessity of regeneration is underscored in John 3 where Jesus states, 'Ye must be born again.' This new birth is not a result of human effort but a sovereign act of God. A sinner, dead in sins, lacks the ability to come to Christ unless God intervenes. As articulated in Titus 3:5, 'Not by works of righteousness which we have done, but according to His mercy He saved us, by the washing of regeneration and renewing of the Holy Ghost.' Here, regeneration is highlighted as God's merciful action, enabling the unbeliever to respond to the gospel with faith. Without this divine intervention, the natural inclination of the human heart is to love darkness rather than light, thus emphasizing our utter dependence on God's grace for salvation.