1 Therefore, since we have this ministry, as we received mercy, we do not lose heart, 2 but we have renounced the hidden things of shame, not walking in craftiness or adulterating the word of God, but by the manifestation of truth commending ourselves to every man’s conscience in the sight of God. 3 And even if our gospel is veiled, it is veiled to those who are perishing, 4 in whose case the god of this age has blinded the minds of the unbelieving so that they might not see the light of the gospel of the glory of Christ, who is the image of God. 2 Corinthians 4:1-6 (LSB) Read verses 5-6 on the site.
Carefully read the passage I placed at the top of this post (2 Corinthians 4:1-6). What is the Apostle Paul saying here? The Gospel that he preached, the other Apostles preached, which was passed on to them from Christ himself, is understood and obeyed only by those whose hearts have received the light which God has shone into the darkness in their hearts to give light to the light of the knowledge of the glory of God in the face of Jesus Christ.
That being true, those who attack this very same Gospel are unbelievers whose minds have been blinded by the god of the world (Satan) to keep them from seeing the light of the gospel of the glory of Christ, who is the image of God. These very same unbelievers are the perishing while those who are in the light of the gospel of the glory of Christ are the living because they possess eternal life in Christ.