The fool has said in his heart, “There is no God.” They are corrupt, and have done abominable iniquity; There is none who does good.
2) God looks down from heaven upon the children of men, To see if there are any who understand, who seek God.
3) Every one of them has turned aside; They have together become corrupt; There is none who does good, No, not one. ~~Psalm 53:1-3
In God's Constitution (the Bible), the term does not indicate mental incompetence, but moral and spiritual insensitivity. The fool is the individual that ignores the King's principles, laws and precepts. Without any laws, there would be nothing but chaos and mayhem on a consistent basis.
Remember, at some stage of life, we were all disobedient to the King's command and His principles. When we fail to embrace His principles and commands, we fall into an environment that causes us to stray from the very thing that can strengthens us and assists us in our growth. To truly know your position in the presence of the King, you must have the Holy Spirit residing in your temple (meaning your body). Remember what the King stated:
the Holy Spirit will take up residence in your life.
He will guide you.