Proverbs 25:4-5; Proverbs 25:21-22

4 Remove the dross from silver, and the sterling will be ready for the silversmith. 5 Remove the wicked from the king's court, and his reign will be made secure by justice.
21 If your enemies are hungry, give them food to eat. If they are thirsty, give them water to drink. 22 You will heap burning coals on their heads, and the LORD will reward you.