It is commonplace to either understate the reality of evil or froth at the mouth about it. I doubt these two misrepresentations are exclusively Christian, but we do them well. Some Christians are still stuck in the Enlightenment's hope of progress, and think that with greater education, the curtailing of religious mania, and greater justice in the world evil would essentially evaporate. Such Christians are offended or embarrassed by the inclusion of 'evil' in the public life of the church, and edit out mention of it in, for example, the baptismal liturgy.
And then there are those Christians who seem to be obsessed with evil to the extent that human agency within it disappears, or certain people are identified entirely with evil. While I have some sympathy with that identification, those who do this seem to spread the just wide enough to catch those they don't like. (A tendency a bit evil in itself.) And the obsession with evil is then perverted still further by Hollywood which makes evil almost sexy (in a perverted way) or so 'other-worldly' that people are distracted from its actual locale. And I should also mention the teenage attraction to evil/demons which seems to derive from either self-hate or plain old teenager rebellion.
So what are we meant to think of evil? Well, first, it is real. Second, it isn't like Hollywood. It is to be found in the lives of real people, and manifests itself in individual perversion right up to whole societies. Third, it isn't sexy either, more banal than anything (but don't let this fool you, evil kills and destroys. Hannah Arendt attached the label of 'banal' to evil in her reporting of the Eichmann trial and the evil of Nazism.) And yes, I think sometimes people earn the appellation 'evil', although not necessarily for good. I looked into the eyes of a drug-crazed maniac yelling satanic abuse in my face from two inches away while he had a screwdriver poking in my belly. Two lives were lost after that night, and it doesn't feel like I was encountering 'merely' human failure that night. He was in the power of evil.
St Paul is right when he says that we are in conflict with more than flesh and blood (Eph 6:10-17); but we don't meet it apart from flesh and blood. It is close to each one of us in the distortions that make up our psyches, and the compounding historical perversions and distortions embedded in our global human community (and in each one of us; just as the doctrine of Original Sin says, we are sinners even before we 'sin'). Evil is opposed (personally and communally, historically and spiritually) through the traditional spiritual disciplines (including good counselling) and in our opposition to social movements of oppression and terror. And if you are really serious about opposing evil in your own heart and in the world, then truth, justice, peace and faith are essential.
Ultimately, evil is defeated on the cross and in the resurrection. Jesus' self-surrender and desertion by the Father to the power of evil, in utter openness to its power, defeats it. This is the truly disturbing heart of Christianity. Some atonement theories, and some interpretations of them, make the cross and resurrection in some way an overpowering of evil, as though God's power is of the same kind as evil, just of a greater magnitude. God's power in Christ is of an entirely different order, the power of self-sacrificing love given over to the power of evil and death. And in the apparent defeat of the cross, when all seems lost in the 'slabby darkness' of the tomb, there we discover that evil was 'tricked' (as the Fathers said in a variety of ways). The powerlessness of love overcomes evil in its (love's) powerlessness. Luckily God did it for us on the cross and resurrection because I don't have the courage to do it in my own life. If that terrible night with the man with the screwdriver was replayed I wouldn't give myself over to the evil, or watch as someone else fell into its power.
Ultimately, evil is defeated on the cross and in the resurrection. Jesus' self-surrender and desertion by the Father to the power of evil, in utter openness to its power, defeats it. This is the truly disturbing heart of Christianity. Some atonement theories, and some interpretations of them, make the cross and resurrection in some way an overpowering of evil, as though God's power is of the same kind as evil, just of a greater magnitude. God's power in Christ is of an entirely different order, the power of self-sacrificing love given over to the power of evil and death. And in the apparent defeat of the cross, when all seems lost in the 'slabby darkness' of the tomb, there we discover that evil was 'tricked' (as the Fathers said in a variety of ways). The powerlessness of love overcomes evil in its (love's) powerlessness. Luckily God did it for us on the cross and resurrection because I don't have the courage to do it in my own life. If that terrible night with the man with the screwdriver was replayed I wouldn't give myself over to the evil, or watch as someone else fell into its power.