David vows to put his trust in god to destroy his enemies. Are there no other reasons to pray to god?
Blah, blah, blah. Save David from his enemies whose teeth are like arrows and whose tongues are like swords. Sounds like David is on the outs in the 7th grade playground.
If you thought David had said all there is to be said about the wicked, you would be wrong. Nope, now we find out that they're wicked from the get-go, telling lies straight out of the womb. They're poisonous and can't be won over by the righteous. The only thing that can be done is for god to break their teeth, cut them into pieces and melt them as a snail (v. 8). Then the righteous can have a party and bathe their feet in blood. Sounds like an awesome kegger!
More on David's enemies: god should kill them for barking like dogs and burping, and he should laugh while he's doing it. I'd laugh if they can burp the alphabet, because I'm five. In the same verse (10) David asks the god of mercy...[to] let me see my desire upon mine enemies, which doesn't seem very merciful to me. Oh, except in the next verse he asks god not to kill them, just to strip them of their power and scatter them and turn them into beggars.
David asks god to stop the earthquakes and the wine of astonishment (v. 3) because of that time Joab killed 12 000 people. God actually replies, listing the countries he likes and doesn't like. Good: Gilead, Manasseh, Ephraim, Judah, Philistea. On the outs: Moab (a washpot), Edom (he threw a shoe). David asks god to give him the strength to conquer Edom