What does Psalm 5:9 mean?
David's prayer includes a description of his enemies (Psalm 3:1). They are deceitful, malicious, given to corrupt language, and flatterers. Absalom, David's son, had won a large following through flattery and deceit (2 Samuel 15:1–6), and he and his men pursued David in an effort to kill him (2 Samuel 15:13–14).David was completely different from Absalom. Despite the attempted coup and murder, David commanded his men not to harm Absalom. Second Samuel 18:5 records his orders to Joab, Abishai, and Ittai: "Deal gently for my sake with the young man Absalom." However, Joab disobeyed David's order; he and his armorbearers killed Absalom (2 Samuel 18:14–16). When David heard about this killing, he mourned deeply, crying out, "O my son Absalom, my son, my son Absalom! Would I had died instead of you, O Absalom, my son, my son!" (2 Samuel 18:33). David believed vengeance belonged to the Lord.
Even when severely persecuted, God's people should not retaliate but leave matters in the Lord's hands. Romans 12:19 commands: "Beloved, never avenge yourselves, but leave it to the wrath of God, for it is written, 'Vengeance is mine, I will repay, says the Lord.'"