We can learn from the example of Yosef towards his brothers that one should never seek revenge against a person who causes him any harm or distress or damage. Rather, one should repay even a guilty offender with kindness [Tanya Ch 12]
Why should we be kind to guilty offenders?
Because whatever that person did to you ultimately stems from God. The person was merely an agent from God, Who decreed that this thing should occur to YOU. Thus, since ''everything that God does is for the good'' [Brachot 60b], you must repay the person - who brought this ''good'' to you - with kindness.
Source: Lubavitcher Rebbe, Likutei Sichos Vol 5 p. 247
Note: this is not referring to someone who is trying to kill you.... for more information on this see The Jew's Double Standard