Proverbs 25:20-22

Complete Jewish Bible

²⁰ Like removing clothes on a chilly day or like vinegar on soda
    is someone who sings songs to a heavy heart.

²¹ If someone who hates you is hungry, give him food to eat;
    and if he is thirsty, give him water to drink.
²² For you will heap fiery coals [of shame] on his head,
    and Adonai will reward you.