David, or whoever wrote this one, complains about god ignoring him in times of trouble, thus allowing the wicked and godless to pick on the weak. I'm sensing a theme here. The middle bit is a list of crimes committed by atheists, ending with a rousing call to god to punish them by breaking their arms and banishing them while rewarding the oppressed.
David apparently 'wrote' this before he met Abishag, because instead of seeking solace in a comely young virgin, he wants god to provide it and is hurt when the lord's advice is to flee. He wants to know what to do when his institutions collapse, because god is up there watching and judging and raining fire and brimstone down on his enemies.
David asks god to help because the righteous are being taken over by the wicked. It's Eurabia all over again! Apparently the problem is everybody is lying and claiming it's 'free speech', so David calls on god to cut off the liars' lips and tongues. Well, that's one method of contract enforcement, I suppose. You could also, say, develop contract laws and courts. God finally speaks and says he'll help the needy, but as far as this Psalm goes, he's all talk no action.
Even though god just talked to him in the last chapter, David is whining again about feeling neglected, though he continues to express undying love and faith.
To a man, atheists are corrupt good-for-nothing fools. God, watching from heaven, tries to determine if any of us is truly righteous. Again, wouldn't an omniscient god... know? Does he really have to check our Facebook statuses to see who's in a relationship with him or seeking 'play'? Anyway, god decides that no one is good and despairs at the wicked, though he does nothing to convince them to change their ways, he only promises vague action, some time in the future, that will please Jacob.
David is concerned about zoning legislation. Specifically, he wants to know who can go into the tabernacle and who can live on the hill. He decides it's only the righteous and honest who neither slander their neighbours nor hurt them, keep their promises, lend their money without interest and can't be corrupted in court testimony. I'm flabbergasted. I really thought it was going to be the wicked and the liars.