From Treasury Of Scripture Knowledge:
(Proverbs 24:29 [NIV]) Do not say, "I'll do to him as he has done to me; I'll pay that man back for what he did."
(Romans 12:17-19 [NIV]) Do not repay anyone evil for evil. Be careful to do what is right in the eyes of everybody. If it is possible, as far as it depends on you, live at peace with everyone. Do not take revenge, my friends, but leave room for God's wrath, for it is written: "It is mine to avenge; I will repay," says the Lord.
(1 Peter 3:9 [NIV]) Do not repay evil with evil or insult with insult, but with blessing, because to this you were called so that you may inherit a blessing.