A strange, ancient practice used as a metaphor occurs in Proverbs 25:22 and in Romans 12:20. The metaphor is based on an apparent practice of a guilty party being forced to carry a container of burning coals on his head. Some scholars think the practice was common in Egypt; the intent seems to be to motivate a guilty party to repent of his actions. The writer of Proverbs and the apostle Paul both cite the practice (as a metaphor) when encouraging charitable actions toward one’s enemy. In other words, charitable actions toward an enemy may motivate him to repent of his evil deeds.

There are examples in Scripture of feeding and clothing enemy captives in times of war (2 Kings 6:22; 2 Chronicles 28:15), and exhortations against seeking vengeance against those who have hurt you (Romans 12:14, 17-21). Jesus corrected a Jewish tradition that allowed for hating one’s enemies: “Love your enemies, bless those who curse you” (Matthew 5:43-44).

If you have been hurt, follow Jesus’ example and be kind. 

The success of the Gospel exasperates its enemies.
Matthew Henry