We definitely have a God-given ability, and responsibility, to fight against evil; one thinks of Christ cleansing the Temple. Indeed all the traditions allow for the exercise of “holy indignation”, though at the same time they all equally caution that such indignation is to be directed in the first instance against our own fallen nature. One thinks of the distinction in Islam between the greater and the lesser jihad. In much the same vein the Fathers teach that when the Psalms talk about slaying enemies, this is in reference to fighting the demons and endeavoring to exterminate sinful thoughts when they are still small (hence the “Babylonian babies” of Psalm 137) and before they turn into passions.
The problem, of course, is that like everything God gave us we’ve managed to corrupt and pervert our fighting capacity, using it not in defense of justice, whether inward or outward, but for our own selfish ends. Indignation is then far from holy! We simply want to “get back at” the people who’ve harmed us or—even more reprehensibly—who’ve simply gotten in the way of our getting what we want. The way, or at least one way, to begin again using this capacity in a way Heaven would approve is to realize that “turning the other cheek”, rather than a sign of weakness or wimpiness, is actually a manifestation of real power. The Taoists are especially good on this point, the Tao Teh Ching being perhaps the best book in the world for showing how true strength is to be found, paradoxically, in seeming weakness.
Do you know the story about the Imam Ali? Engaged in a campaign of the lesser jihad, it seems he had an enemy pinned to the ground and was about to cut off his head when the man spat in his face. Ali immediately put his sword back in its sheath and walked away. When asked what in the world he was doing, he explained to his companions, “I refuse to kill when I am angry.”