2 Corinthians 4. Therefore, having this ministry by the mercy of God, we do not lose heart. We have renounced disgraceful, underhanded ways; we refuse to practice cunning or to tamper with God’s word, but by the open statement of the truth we would commend ourselves to every man’s conscience in the sight of God. And even if our gospel is veiled, it is veiled only to those who are perishing. In their case the god of this world has blinded the minds of the unbelievers, to keep them from seeing the light of the gospel of the glory of Christ, who is the likeness of God. For what we preach is not ourselves, but Jesus Christ as Lord, with ourselves as your servants for Jesus’ sake. For it is the God who said, “Let light shine out of darkness,” who has shone in our hearts to give the light of the knowledge of the glory of God in the face of Christ.

The spiritual masters taught that one of the immediate effects of the sin of lust is a blinding of the intellect. The intellect is meant to know the truth and discern truth from error. Most people are dead in their sin and up to their eyes in porn and fornication. They are completely blind to the truth and reality because they have divorced themselves from Jesus Christ, who is the truth itself, by their sin.