What does Psalm 14:3 mean?

Here, David shares a sentiment later echoed by Isaiah 53:6: "All we like sheep have gone astray; we have turned—every one—to his own way." History depicts humanity beginning with fellowship with God in the garden of Eden (Genesis 2:15). However, sin disrupted that fellowship (Genesis 3:6), and since then the human race has been on a downward path away from God. In this verse, David portrays mankind as "corrupt." This is translated from a Hebrew term, 'alach, meaning "rotten, putrid, or decayed," with an emphasis on moral perversity or depravity.

Because of this corruption, no person is capable of any deed which an omnipotent, omniscient, all-good God would consider truly "good." God created human beings to glorify Him, but since sin entered humanity, individuals have chosen to go their own way and do their own thing. Far from glorifying God, they glorify themselves.

Daniel 4:29–30 reveals that while Nebuchadnezzar was walking on the roof of his royal palace, he boasted, "Is not this great Babylon, which I have built by my mighty power as a royal residence and for the glory of my majesty?" That self-glorification led to his humiliation (Daniel 4:31–33).