What does the Bible say about denying the existence of God?

Psalm 53 articulates that the fool has said in his heart, 'There is no God,' underscoring a moral failing rather than simply a lack of intelligence. This declaration against God results in moral decay and a state of rebellion against divine authority. The psalm illustrates that denying God leads to an absence of moral direction, as He is the ultimate standard for right and wrong. It's a profound folly to reject the evidence of God's existence, which is apparent in creation and human conscience.