Some Ans. Questions 2014 by -'Abdu'l-Bahá- 1 Para

For example, if someone wrongs, injures, and assaults another, and the latter retaliates in kind, this constitutes revenge and is blameworthy. If Peter kills the son of Paul, Paul has no right to kill the son of Peter. Were he to do so, it would be an act of vengeance and blameworthy in the extreme. Rather, he must act in the opposite manner and show forgiveness, and, if possible, even be of some assistance to his aggressor. This indeed is that which is worthy of man; for what advantage does one gain from revenge? The two actions are indeed one and the same: If one is reprehensible, so too is the other. The only difference is that one preceded the other (77:5)

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