Compare this verse with Psalm 11:6, also written by David. In this verse, David continues to demand that the enemies receive what they had planned for David. David connects here with the law of retaliation (Exodus 21:23–25).
As New Testament believers we however also need to consider what Jesus Christ has taught us.
In Matthew 5:38–42, Jesus says that in his kingdom we are to turn the other cheek
—to return evil with good. This is not completely new, as Proverbs 25:21–22 shows: if you answer the evil of your enemy with good, you will heap burning coals on his head! These burning coals may turn the enemy toward Christ. In Romans 12, Paul quotes this text from Proverbs and subsequently writes in Romans 12:21: Do not be overcome by evil, but overcome evil with good.
David’s great Son sets out for his followers other paths than what his forefather after the flesh here points to: as he has shown to his enemies heavenly love, so his disciples must now do the same. And then one day the day of justice will come!
10 Let burning coals fall upon them! Let them be cast into fire, into miry pits, no more to rise!