Why the Gospel is Veiled

Here's another good explanation on why people don't understand the Gospel, much less believe it:

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 image of God.

2 Corinthians 4:3

The Holy Bible : English standard version. 2001, Wheaton: Standard Bible Society.