How do we know the Holy Spirit is essential for understanding the gospel?

The necessity of the Holy Spirit in understanding the gospel cannot be overstated. As mentioned in John 6:63, 'It is the Spirit that quickeneth; the flesh profiteth nothing.' The Holy Spirit not only empowers the preaching of the gospel but also opens the hearts and minds of those who hear it. Without the illuminating work of the Spirit, the message of the gospel remains hidden from the understanding of sinners, highlighting the completeness of God's initiative in salvation, as He gives life to whom He wills.