For the music director; by David.

There are three voices in this psalm, each followed by a comment: (a) the fool, v1; the Lord, vv2ff; and Israel, v7.  (NBC)

14:1 Fools say to themselves, “There is no God.”
They sin and commit evil deeds;
none of them does what is right.

The fool says in his heart, “There is no God.” – The point is not, ‘The person who denies the existence of God is a fool’, but rather, ‘The fool shows by his foolish behaviour that he does not think that God sees, or knows, or cares about, that behaviour.’

In other words:

‘The atheism in question is more practical than theoretical, not so much denying God’s existence as his relevance.’ (NBC)

The existence of God has no practical importance to him:

‘The “fool” in his heart denies the practical import of God’s existence. He shuts off the affairs of this world from divine intervention and denies any personal accountability to God for his actions (cf. Psa 10:4; 73:11). Within the congregation he may mimic the sounds of faith, but his true self shows disregard for God, his commandments, and his people. He is characterized by an absence of concern or love for others, but he is occupied with himself.’ (EBC)

As Charnock says:

‘Not that he denies the existence of a supreme being that created the world, but his regarding the creatures, his government of the world, and consequently his reward of the righteous or punishments of the wicked.’ (The Existence and Attributes of God)

There is, indeed, madness in this:

‘Every man, so long as he lieth unrenewed and unreconciled to God is nothing in effect but a madman.’ (Dickson)

Indeed, this unbelief is more extreme than that of the devil:

‘He that doth not believe that there is a God, is more vile then a devil. To deny there is a God, is a sort of atheism that is not to be found in hell.’ (Thomas Brooks)

And yet it suits him to be a practical atheist:

‘No man says, “There is no God” but he whose interest it is there should be none.’ (Augustine)

Yet none of this detracts from the reality of God:

‘Were all human beings suddenly to become blind, still the sun would shine by day and the stars by night, for these owe nothing to the millions who benefit from their light. So, were every man on earth to become atheist, it could not affect God in any way. He is what he is in himself without regard to any other. To believe in him adds nothing to his perfections; to doubt him takes nothing away.’ (A.W.Tozer, The Knowledge of the Holy, 40)

They… – The switch from the singular (‘the fool’) to the plural (‘they’) suggests that these practical atheists, if not actually in the majority, are certainly plentiful in number.

The Humanist Manifesto II, 1973
We believe that traditional dogmatic or authoritarian religions that place revelation, God, ritual, or creed above human needs and experience do a disservice to the human species.

Promises of immortal salvation or fear of eternal damnation are both illusory and harmful. They distract humans from present concerns, from self-actualization, and from rectifying social injustices.

We affirm that moral values derive their source from human experience. Ethics is autonomous and situational, needing no theological or ideological sanction. Ethics stem from human need and interest. To deny this distorts the whole basis of life. Reason and intelligence are the most effective instruments that humankind possesses. There is no substitute; neither faith nor passion suffices in itself.

No deity will save us; we must save ourselves.

Atheism is ‘contrary to nature’

Stephen Charnock:

‘He doth not form a syllogism, as Calvin speaks, that there is no God; he dares not openly publish it, though he dares secretly think it; he cannot rase out the thoughts of a deity, though he endeavours to blot those characters of God in his soul; he hath some doubts whether there be a God or no: he wishes there were not any, and sometimes hopes there is none at all; he could not so ascertain himself by convincing arguments to produce to the world, but he tampered with his own heart to bring it to that persuasion, and smothered in himself those notices of a deity, which is so plain against the light of nature that such a man may well be called a fool for it.’

John Blanchard:

‘Commenting that atheism “may be learned, taught and adapted, but it cannot be neutral”, the British preacher Robert Sheehan gives a simple illustration. A child visiting an art gallery would ask of an exhibit, “Who painted that?” On a visit to a science museum, the question would be: “Who invented that?” As Sheehan writes, “He is by nature a creationist. Paintings have painters, inventions have inventors. Which child (or adult) would naturally ask, “By what process did that painting (or invention) evolve by chance?” … Cross the road to a natural history museum and a child (and adult) would naturally respond in the same way. He would see in God’s handiwork God’s imprint. He would look for a creator…Atheism may be taught, but it is contrary to nature.”‘  (Does God Believe in Atheists? p490f)

14:2 The LORD looks down from heaven at the human race,
to see if there is anyone who is wise and seeks God.
14:3 Everyone rejects God;
they are all morally corrupt.
None of them does what is right,
not even one!

All have turned aside – The converse of ‘not seeking God’, v2, is deliberately ‘turning aside’.

There is no one who does good, not even one – ‘The apostle, in quoting part of this psalm (Rom 3:10, etc.) to prove that Jews and Gentiles are all under sin (v. 9) and that all the world is guilty before God (v. 19), leads us to understand it, in general, as a description of the depravity of human nature, the sinfulness of the sin we are conceived and born in, and the deplorable corruption of a great part of mankind, even of the world that lies in wickedness, 1 Jn 5:19.’ (MHC)

14:4 All those who behave wickedly do not understand—
those who devour my people as if they were eating bread,
and do not call out to the LORD.
14:5 They are absolutely terrified,
for God defends the godly.
14:6 You want to humiliate the oppressed,
even though the LORD is their shelter.
14:7 I wish the deliverance of Israel would come from Zion!
When the LORD restores the well-being of his people,
may Jacob rejoice,
may Israel be happy!

When the Lord restores the well-being of his people – Or, ‘restore the fortunes’.  This phraseology:

‘is characteristic of the prophets as they describe the era of restoration when Israel, restored to the land, will again enjoy the blessings of God (cf. Eze 16:53; Zep 2:7). After the Exile God demonstrated his faithfulness by his renewed blessings, by restoring Israel to the land, and by permitting his temple to be rebuilt. The psalmist anticipates an era when God will vindicate his people and deliver them from the fools who oppress them. In Jesus’ coming Jews and Gentiles are further assured of God’s concern, vindication, and presence with his people (cf. Rom 11).’ (EBC)