Romans 12:20

On the contrary, “If your enemy is hungry, feed him; if he is thirsty, give him a drink. For in so doing, you will heap burning coals on his head.”

Note Proverbs 25:21–22 (see also LXX)

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.

Therefore “If your enemy is hungry, feed him. If he is thirsty, give him a drink; for in doing so, you will heap coals of fire on his head.”

But if thine enemy hunger, feed him; if he thirst, give him to drink: for in so doing thou shalt heap coals of fire upon his head.