20 To the contrary, “if your enemy is hungry, feed him; if he is thirsty, give him something to drink; for by so doing you will heap burning coals on his head.”
Verse 20 advances verse 19 by giving a specific illustration of not taking personal vengeance on someone.
20 To the contrary,
The opposite of taking revenge on someone is to love him with kindness.
The following quotation is a citation from Proverbs 25:21-22 (LXX).
“if your enemy is hungry, feed him;
It takes maturity to take your enemy out to dinner.
if he is thirsty, give him something to drink;
Maturity will have compassion on even an enemy.
for by so doing
“So doing” means by showing hospitality, by returning kindness for injury. We do this by not simply responding to our enemies passively but by doing something proactive. In this we will do the nobler thing. This action is not for our personal ease but for the kingdom’s sake. That is, we have the possibility of winning people to Christ or restoring a friendship among believers.
you will heap burning coals on his head.”
“Burning coals” is a metaphor for deep anguish. Acts of kindness will increase the guilt, shame, or remorse of our enemy’s hostility toward us.
The best way to deal with an enemy is to attempt to turn him into a friend.
It is not enough to passively react to our enemies. We need to take the proactive step of exercising active benevolence for them. Kill them with kindness. No man for whom Christ died can be an enemy to us. There is no possible condition whereby we make those who oppose us our enemies.