Why would Proverbs 25 in the Bible tell us to do this? Well, it’s an expression. If your enemy is hungry or thirsty, give him something to eat or drink, for in so doing you “heap burning coals on his head.” Just as hard metals are melted by putting hot coals on them, a hard heart can be softened by kindness. Try to serve a person who annoys you; show compassion on someone who has hurt you, be respectful toward someone who is difficult to be around. A little kindness might soften their heart.