"The fool has said in his heart,
'There is no God.'"
This is "nabal," the word for fool. Do you remember another Nabal? David does. He married Nabal's beautiful wife Abigail. Nabal was greedy, ungrateful, uncaring, "harsh and evil in his dealings," when David and his men protected his flocks for him. (I Samuel 25:3) Nabal refused to feed them or give them their due. He not only ate their lunch, but was one of whom God said "ate up my people as they eat bread..." (verse 4) God struck the man down in the midst of the prime of his wealth and gave his "intelligent and beautiful in appearance" wife to David. Nabal sounds like the description of what the verse says "There is no one who does good." (verse 1)
A fool has a hard heart.
"But the Lord has looked down from heaven upon the sons of men,
To see if there are any who understand,
Who seek after God.
They have all turned aside;
together they have become corrupt
(KJV: they have all become filthy as in sour, rancid as curdled milk);
There is no one who does good, not even one."
The Lord looked down all right and said, "You there, fool. You don't even appreciate all the wonderful things I have blessed you with, including your spouse. You see, I have this guy over here who will be king one day, but King Saul took away his wife Michal and gave her to another. I think he and your Abigail will get along just great." Then Nabal fell over in a stroke and died. God put Abigail and David on a collision course that resulted in her falling off her donkey before him. This is one of my favorite love stories in the Bible.
A fool has a prickly heart.
(A free bit of advice: if you don't appreciate your spouse, you can bet your booties that there's somebody out there who will. So don't be a nabal. But if you find yourself hitched to a less than pleasant person, don't hold your breath that God will strike him down like He did Nabal and send you a handsome David instead. Usually God has other things to accomplish in your life, like your attitude.)
Adam Clarke says, "Nabal," fool, signifies "an empty fellow (a cotton-headed ninny), a contemptible person, a villain. One who has a muddy head and an unclean heart; and, in his darkness and folly, says in his heart, 'There is no God.' 'And none,' says one, 'but a fool would say so.'"
He goes on to say, "1.) There have been some, not many, who have denied the existence of God.
2.) There are others who, without absolutely denying the divine existence, deny His providence.
3.) There are others, and they are very numerous, who, while they profess to acknowledge both, deny them in their heart, and live as if they were persuaded there was no God to either punish or reward."
Want to hear the good news? It's in verse 6...
"You would put to shame the counsel of the afflicted,
But the Lord is his refuge."
So in the midst of a world of Nabals, when we too long "Oh, that the salvation of Israel would come out of Zion! When the Lord restores His captive people," we can be assured that "Jacob will rejoice, Israel will be glad." (verse 7)