What does Psalm 40:14 mean?

Here, David asks God to defeat and confound those who were seeking to kill him. He wanted those who longed to dethrone him to be disgraced. If we compare the request in this verse with David's words in verse 11, we see that David's prayer for the defeat and disgrace of his enemies was offered with full confidence in the Lord (Psalm 40:11).

Though David was a man of military skill (Psalm 144:1), he didn't seek revenge against his enemies (1 Samuel 24:1–10). In Romans 12, we are told explicitly not to take vengeance into our own hands. Verse 19 states, "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'" (Romans 12:19). Verses 20 and 21 exhort us to show kindness to our enemy and to overcome evil with good.

Instead of taking matters into our own hands, we are instructed to leave them in God's hands. David committed his desperate situation to the Lord. That does not necessarily mean God will take our preferred actions, or steps of vengeance, but He will ultimately make all wrongs right (Revelation 20:11–15).