David had a lot of enemies. At least it sure seems this way from reading the first seven Psalms. Some were political (Cush), some were from his own bad choices (Absalom), some were because of his position (jealousy or rebellion against the king)...
But what I've noticed in these Psalms is that David is relying on God to be his defender. He doesn't take matters into his own hands (well, except for running and hiding in caves and things like that.)
Paul said it this way,
Romans 12:19 NAS
Never take your own revenge, beloved, but leave room for the wrath of God, for it is written, "VENGEANCE IS MINE, I WILL REPAY," says the Lord.
We live in a society where we are told to "fight back," "get them before they get you," and how often have I heard someone say, "I don't get mad, I get even."
17 I will give thanks to the LORD according to His righteousness And will sing praise to the name of the LORD Most High.
Which will you choose?