The enemies lie in wait for David’s life. Like bird catchers set traps for birds or poachers set snares for rabbits, the enemies try to capture him. The metaphor of a trap or a snare is rather common in the Psalms, for example, the preceding and following psalms—Psalm 140:5 and Psalm 142:3. It is David’s prayer that the Lord may prevent him from falling into the hands of the evildoers.
9 Keep me from the trap that they have laid for me and from the snares of evildoers!