We love to take scripture out of context to proof-text our own points, make us feel better about ourselves, and assert out own superiority.
It is no different with the equation of the fool and the man who says in his heart there is no God.
We assume the psalmist is referring to intellectual fools who struggle with issues of faith.
Rather, he is talking about moral fools, people of power who plunder the poor and helpless as if there were no God of justice and truth to whom they must give account.
The proof of reverence for God is, in this context, dealing justly, fairly, and righteously with people - especially, the poor.
"The fool says in his heart, 'There is no God.'
They are corrupt, they do abominable deeds;
there is none who does good."
"The LORD looks down from heaven on the children of man,
to see if there are any who understand,
who seek after God."
"They have all turned aside; together they have become corrupt;
there is none who does good,
not even one."
"Have they no knowledge, all the evildoers
who eat up my people as they eat bread
and do not call upon the LORD?"
"There they are in great terror,
for God is with the generation of the righteous.
You would shame the plans of the poor,
but the LORD is his refuge."
"Oh, that salvation for Israel would come out of Zion!
When the LORD restores the fortunes of his people,
let Jacob rejoice, let Israel be glad."
(Psalm 14 ESV)