heap coals of fire on someone's head

heap coals of fire on someone's head

go out of your way to cause someone to feel remorse. British
This phrase is of biblical origin: ‘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).
See also: coal, fire, head, heap, of, on