How does God bring light into our hearts?

In Reformed theology, the illumination of the heart by God's light is attributed to the work of the Holy Spirit. As noted in 2 Corinthians 4:6, 'For God, who commanded the light to shine out of darkness, hath shined in our hearts, to give the light of the knowledge of the glory of God in the face of Jesus Christ.' This transformative act occurs when the Holy Spirit applies the truth of the gospel to a believer’s heart, enabling them to understand their sinfulness and their need for Christ's redemptive work. This process is essential for salvation and sanctification, as it divides the believer from the darkness of their former life and draws them into the marvelous light of God, fostering a genuine love for Him and a longing for righteousness.