If you have ever been in a place where you fear some secret invasion, or an attack from some unseen enemy, you can appreciate the imagery here. The enemy has found a place to hide and pounce when the righteous one is not ready. The psalmist asks God to catch his enemy by surprise and ambush him. The result will be that people will wag their heads as if to say “he never saw that coming.” The secret strike was the LORD’s, and the righteous one can rejoice.
LORD, we trust you. We know you are watching when no one seems to be watching.
Psalm 64