To retaliate upon an oppressor

As is referred to in this Statement of Allah: "Allah does not like that the evil should be uttered in public except by him who has been wronged. And Allah is Ever All-Hearer, All-Knower." (V.4:148) "And those who, when an oppressive wrong is done to them, take revenge." (V.42:39) Ibrahim said, "They disliked to be humiliated, and when they were powerful, they would forgive (their oppressors)."