In this passage I found the description of the evil ones the most interesting. Here is the way they work:

1. They plan evil
2. They gather to do evil together
3. They sharpen their tongues
4. They try to make others stumble
5. They hide snares, traps and nets for people

And I find it refreshing that even though we all hear the "turn the other cheek" stuff in the Bible, David is REAL in that he cries out for God to trip up the evil doers - even unto death. He requests that God "maintain the cause of the afflicted" and ensure "justice for the poor."

I was raised to understand:

world = pain, no justice
heaven = no pain, justice

But I love that David cries out for there to be justice on earth too.

Psalm 140:1-13