There is nothing like Good or evil. Just like absence of Light is darkness in the same way absence of good might be called evil. With this definition, "evil" is not its own entity. But who categorises what is good or evil. Is there an objective yardstick for good and evil? What is the protocol exactly based on? I believe it’s our conscience that tells us the difference between good and bad deeds. What if a person actually believes that what he is doing is right and the other person who can’t see his point of view thinks the exact opposite thing. It’s then called a matter of perspective. Ain’t this the whole reason for nations at War? Everybody knows taking human life is an ill deed. Yet some do it in the name of religion and are called evil while others do it to subdue that evil by taking toll of human life a notch higher and justify themselves as good? Post cold war strife continues among nations and religious groups. In our families, neighbourhoods, cities and most importantly within ourselves. War, violence, injustice, intolerance and oppression continue despite our best efforts because everyone thinks they are right from their point of view. Figures like Hitler and Stalin were (from their perspective) trying to do what they thought was best for their people and for the world as a whole. As the Japanese proverb says we have three faces. “The first face you show to the world, the second face you show to your close friends and family. The third face you never show anyone. It is the truest reflection of who you are.” Even looking back to the original conflict between God and Iblis/Satan, from Iblis's perspective he wasn't intentionally trying to disobey God just for the sake of it. He was only trying to make a point about how he shouldn't have to bow to someone inferior to him, so from his own perception he was justified in what he said. Each 'wrongdoer' has a very real conviction that what they're doing is in some way for the purpose of what they perceive as being 'good' in order to uphold their perception of honour and integrity.
In another man's mind and understanding thy evil cannot subsist, nor in any proper temper or distemper of the natural constitution of thy body, which is but as it were the coat or cottage of thy soul. Wherein then, but in that part of thee, wherein the conceit, and apprehension of any misery can subsist? Let not that part therefore admit any such conceit, and then all is well. Though thy body which is so near it should either be cut or burnt, or suffer any corruption or putrefaction, yet let that part to which it belongs to judge of these, be still at rest; that is, let her judge this, that whatsoever it is, that equally may happen to a wicked man, and to a good man, is neither good nor evil. For that which happens equally to him that lives according to nature, and to him that doth not, is neither according to nature, nor against it; and by consequent, neither good nor bad.