From Dawn Eden:
I think Paul has the answer for you, in Romans 12:19-21, where he references Deuteronomy 32:35 and Proverbs 25:21-22:
"Dearly beloved, avenge not yourselves, but rather give place unto wrath: for it is written, Vengeance is mine; I will repay, saith the Lord.
"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.
"Be not overcome of evil, but overcome evil with good."