Hide Me from the Secret Plots of the Wicked

David's prayer to God to protect him against his enemies. We know that David had many physical enemies, such as Saul and later the enemy nations which he had to fight against. But the enemy in this psalm uses secret plots, uses their tongue to lie and shoot in secret using words.
These enemies plot evil schemes rather than attack directly in battle. They "lay snares secretly" and "devise iniquities" and "shrewd schemes". So these particular enemies may be in David's court itself. In fact David did face a plot of rebellion from his son Absalom.
In any case, David's way to battle such enemies, like other enemies, is to bring it before God. He trusts that God will be just and will fight for those who are righteous and upright.

Psalm 64
To the Chief Musician. A Psalm of David.
 1 Hear my voice, O God, in my meditation;
         Preserve my life from fear of the enemy.
 2 Hide me from the secret plots of the wicked,
         From the rebellion of the workers of iniquity,
 3 Who sharpen their tongue like a sword,
         And bend their bows to shoot their arrows—bitter words,
 4 That they may shoot in secret at the blameless;
         Suddenly they shoot at him and do not fear.
        
 5 They encourage themselves in an evil matter;
         They talk of laying snares secretly;
         They say, “Who will see them?”
 6 They devise iniquities:
         “We have perfected a shrewd scheme.”
         Both the inward thought and the heart of man are deep.
        
 7 But God shall shoot at them with an arrow;
         Suddenly they shall be wounded.
 8 So He will make them stumble over their own tongue;
         All who see them shall flee away.
 9 All men shall fear,
         And shall declare the work of God;
         For they shall wisely consider His doing.
        
 10 The righteous shall be glad in the LORD, and trust in Him.
         And all the upright in heart shall glory.