This is a Ps. on a familiar theme. The Psalmist's life is in danger. He describes the injurious words and malicious plans of his enemies, and foretells how their overthrow will be a warning to all who see it, and a new ground for the righteous to rejoice in God. The same figure (shooting an arrow) is employed both for the assaults of the wicked and for their discomfiture by God.
Psalms 64:1-10
1 Hear my voice, O God, in my prayer: preserve my life from fear of the enemy.
2 Hide me from the secret counsel of the wicked; from the insurrection of the workers of iniquity:
3 Who whet their tongue like a sword, and bend their bows to shoot their arrows, even bitter words:
4 That they may shoot in secret at the perfect: suddenly do they shoot at him, and fear not.
5 They encourage themselves in an evil matter:a they commune of laying snares privily; they say, Who shall see them?
6 They search out iniquities; they accomplish a diligent search: both the inward thought of every one of them, and the heart, is deep.
7 But God shall shoot at them with an arrow; suddenly shall they be wounded.
8 So they shall make their own tongue to fall upon themselves: all that see them shall flee away.
9 And all men shall fear, and shall declare the work of God; for they shall wisely consider of his doing.
10 The righteous shall be glad in the LORD, and shall trust in him; and all the upright in heart shall glory.