Do not be a witness against your neighbor without cause, For would you deceive with your lips? Do not say, “I will do to him just as he has done to me; I will render to the man according to his work.” (Prov 24:28-29)
Within this portion God gives us guidance. If faced with an ‘unfair’ situation, there is One who will render to each according to his work. We need not react, repay or revenge. Vengeance belongs to God. We are free to do His will.