"If your enemy is hungry, give him bread to eat; and if he is thirsty, give him water to drink; for so you will heap coals of fire on his head, and the LORD will reward you." (Proverb 25:21-22)
There is a place in the New Testament where the Apostle Paul uses the ideas in this verse while discussing one of the many aspects of having Jesus as our Lord:
"Therefore 'IF YOUR ENEMY IS HUNGRY, FEED HIM; IF HE IS THIRSTY, GIVE HIM A DRINK; FOR IN SO DOING YOU WILL HEAP COALS OF FIRE ON HIS HEAD.' Do not be overcome by evil, but overcome evil with good." (Romans 12:19b-21)
I've seen many people quote Proverb 25:21 with delight - imagining with glee how bad it would be for their enemy to experience the horrible pain of being burned by those "coals of fire on his head."
This is taken completely out of context. This verse isn't given twice in the Bible to encourage us to torment those who are harming us and making themselves our enemies. Not at all.
To the contrary, Paul tells us in his epistle to:
"Bless those who persecute you; bless and do not curse." (Romans 12:14)
and he says:
"Repay no one evil for evil. Have regard for good things in the sight of all men." (Romans 12:17)
The truth is that, should our enemies not repent, they will have plenty of time to experience pain for harming Christians...children of the Most High God.
"Beloved, do not avenge yourselves, but rather give place to wrath; for it is written, 'VENGEANCE IS MINE, I WILL REPAY,' says the Lord." (Romans 12:19a)
The call to heap coals of fire on the heads of our enemies is not meant to torment them with physical pain at all.
The geographical context of this verse is that it was written to desert dwellers. If a person was not able to keep a fire going in his home or campsite he would die of exposure to the cold desert night and would have no way of cooking his food.
Putting a pile of burning coals in the container that many carried on their heads assured even one's enemy of a way to feed himself and keep himself warm.
It was an act of kindness.
Blessing those who curse us goes COMPLETELY AGAINST the world system that urges us to help the devil divide and conquer people.
Sometimes it heals that divide and causes reconciliation.
Sometimes it causes the enemy we bless to consider what they are doing to us and others. Sometimes it opens their hearts to the conviction of the Lord as He blesses them through us.
Sometimes THAT torments them....but its the GOOD torment...true, earned guilt....that might lead them to repentance.
May we trust the Lord to take His revenge on our behalf.