Proverbs 25:21-23 NIV

21 If your enemy is hungry, give him food to eat; if he is thirsty, give him water to drink.
22 In doing this, you will heap burning coals on his head, and the LORD will reward you.

References for Proverbs 25:22

23 Like a north wind that brings unexpected rain is a sly tongue—which provokes a horrified look.