LEV717 But why is it that in regard to all other traits and actions, Jews should imitate the behavior of God, and only in the case of revenge does God operate alone, not wanting His actions to be emulated? Perhaps it is precisely because revenge is such an intense and volatile feeling that God forbade it completely from the realm of man's actions. Human beings would not know how to use this feeling properly and repay a wrong in the proper proportion. Just as Cain murdered Abel as revenge for a sacrifice favored by God, which was certainly an "overreaction," perhaps no person can properly control rage and feeling the need for revenge, and therefore cannot administer it properly against another human being who is deserving of punishment. That is why it is left only to God to take revenge and avenge a sin properly, in a way that is exact compensation for a wrong committed. Chizkuni implies as much when he says that only God can assuage the feeling of revenge within man. [Chizkuni commentary on this verse].