‘For the Chief Musician. Of David.'
This is yet another psalm dedicated to the Choirmaster and part of the Davidic collection.
‘The fool has said in his heart,
There is no God.
They are corrupt, they have done abominable works,
There is none who does good.'
A general verdict is passed on mankind. They behave like fools because they reject the idea of God as the one to Whom they are accountable. They have many gods, they worship idols who but represent aspects of creation, but in their hearts they reject the living God who speaks to them through the wonder of creation and through their consciences. They say that there is no such God. See Romans 1:18-23.
‘The fool.' This is rather describing the morally perverse person who rejects the idea of living a godly life. ‘Folly' in the Old Testament is a term used to describe the person who behaves foolishly in that he forgets or misrepresents God or refuses to do His will (Deuteronomy 32:6; Deuteronomy 32:21; Job 42:8; Psalms 74:18; Psalms 74:22), he commits gross offences against morality (2 Samuel 13:12-13) or sacrilege (Joshua 7:15), or he behaves churlishly and unwisely (1 Samuel 25:25). See also Isaiah 32:5-6. Inevitably he always sees himself as wise.
‘In his heart.' It is not his intellect that rejects the idea of God, but his will and emotions. He does not want to have to face up to God because of what it might involve in a transformed life. He likes living as he is. See Psalms 73:11; Jeremiah 5:12; Zephaniah 1:12.
‘They are corrupt, they have done abominable works.' Compare Genesis 6:11. They are corrupt within and their lives reveal what they really are, sinful, violent, idolatrous, sexually perverted. See Romans 1:18-32.
‘There is none who does good.' This is the final verdict on the world. All mankind are fools in this sense, for sin is folly. The difference is that some have found forgiveness. God is declaring that there is no true, positive, untainted goodness in the world. All have sinned and come short of the glory of God (Romans 3:23). All are likewise guilty.