Psalm 36

Transgression speaks (like and oracle) to the wicked (godless) (deep) within his heart; there is no fear (dread) of God before his eyes. For he flatters and deceives himself in his own eyes thinking that his sinfulness will not be discovered and hated (by God).

In many cases, a person who rejects God has become a God unto themselves. They rely on their wisdom and feelings to deal with a matter. The layers of sin have compiled until blindness has covered their eyes. They get to the point where they cannot see the gospel’s truth unless a shock happens or prayer breaks through to the heart.