I'm assuming you have read the entire chapter of Romans 12?
"Therefore if thine enemy hunger, feed him; if he thirst, give him drink: for in so doing thou shalt heap coals of fire on his head." -- Romans 12:20
And please don't tell us "coals of fire" is a pleasant thing as some RC asserted last year. Here is what God means by "coals of fire."
Yea, he sent out his arrows, and scattered them; and he shot out lightnings, and discomfited them." -- Psalm 18:13-14"The LORD also thundered in the heavens, and the Highest gave his voice; hail stones and coals of fire.