This is the second post in a series on Good and Evil.
Can Christians kill bad guys? Can we even say that there are bad guys?  Or to frame the question in a more precise way: may Christians, following Christian principles, legitimately use violence to stop evil?
It’s an old question.  Reasonable responses range from unconditional pacifism to just war theory.  When a team of Navy SEALS killed Osama bin Laden, Christian commentators voiced opinions along most of this spectrum.
Before wading into the fray about how Christians should respond to evil, I need to say something about good and evil themselves.  What are good and evil? How does one distinguish the one from the other?
This is where you might expect me to say something about moral law and divine justice.  Well, that will come in due time.  
First, I want to talk about posture.  
As odd as it may sound, our physical posture provides a helpful metaphor for understanding our spiritual posture.  And good and evil are matters of spiritual posture.

Good posture allows us to maintain our balance with the minimum of effort, and it facilitates breathing and circulation.  Aesthetically pleasing, good posture also suggests poise and grace.  Just think of how easy it is to spot a trained dancer in a crowd.
By contrast, poor posture results in muscle pain, nerve pain and constriction of blood flow.  Whether or not it seems fair, slouching can connote indifference, disrespect, and sloth.
Notice here that I am talking about posture as a habit of holding our physical frame.  I don’t have in mind congenital conditions like scoliosis and kyphosis.
Good posture can be thought of as cooperating with gravity.  Holding ourselves in a way that puts the least strain on our supporting muscles and our ligaments.  
We sometimes slump into our chairs or walk with our shoulders hunched forward because we’re tired or sad or preoccupied.  If this is an exception to the rule, we may suffer a little stiffness but otherwise no harm is done.  
The difficulty comes when we make a habit of slouching and slumping and drooping and sagging.  In time this way of standing and sitting becomes second nature.  We can do lasting harm to ourselves that diminishes our quality of life and requires medical intervention.
So, what does all of this have to do with Good and Evil?
Let’s start at the very beginning.  Genesis.  Chapter One.
God created all that is and saw that it was good.  In other words, he created everything with the right posture toward him and toward everything else in his Creation.  God’s moral law is less a set of discrete rules for separate actions as it is the principle by which everything hangs together.  It’s like gravity.
We humans can practice good posture.  In other words, we can cooperate with divine gravity and hold ourselves habitually in a way that promotes wholeness and health.  
We can choose how we will stand and sit, but we can no more choose the effects of our spiritual posture on our spiritual condition than we can determine the effects of our physical posture on our bodily health.  Gravity is gravity.
Bad spiritual posture amounts to turning ourselves away from God and away from each other, even though divine gravity pulls us toward right relation with our Creator and with our fellow human beings.  
Bad spiritual posture is a resistance to divine gravity, to the way of God.  The result is an increasingly disfigured and tortured life.
Here is where the metaphor begins to break down.  My bad physical posture may be an eyesore to you, but in the end it won’t hurt you.  By contrast, spiritual posture by its very nature seeks to pull others down with it.  Evil is destructive.
There’s also an important catch here that will figure prominently in how Christians respond to evil.  We can do something about our bodily posture.  Just check out the Web.  There are exercises to strengthen our core and to learn good standing and sitting habits.
As far as our bodies go, we can straighten ourselves up.
But the Gospel tells us that we start in a very different place.  God is not standing at a distance waiting for us to straighten ourselves up.  Instead, he sees clearly that our posture holds us captive.
Paul puts it famously in this passage:
For I do not do what I want, but I do the very thing I hate. Now if I do what I do not want, I agree that the law is good. But in fact it is no longer I that do it, but sin that dwells within me.  (Romans 7:15b-17)
In other words, my posture has gotten the better of me.
Paul does not, however, go on to provide seven steps to healthy spiritual posture.  There are no self-help instructions in Romans or anywhere else in Paul’s letters or the Gospels.
Instead, he says this: 
Wretched man that I am! Who will rescue me from this body of death? Thanks be to God through Jesus Christ our Lord!  (Romans 7:24-25)
Just as divine gravity draws us toward a right posture toward God and toward others, forces beyond our control tip us toward destructive and self-destructive postures.  
The intervention of Jesus Christ and the power of the Holy Spirit make it possible for us to cooperate with God’s gravity.  Nevertheless, there remain forces that will buffet us and push us toward a twisted bearing.
In the final analysis, my response to evil is not my response to slights done to me personally.  My hurt feelings, my hurt pride or my wounded soul are not the measure of someone else’s evil.  These experiences should not guide my responses to someone else.  That begins to look rather a lot like revenge.
Instead, when we begin to respond to evil we must be sure that we’re confronting a spiritual posture that tears the fabric of God’s creation.  Evil is a posture that resists God and degrades and debases his children as a matter of ingrained habit.
In the following posts I will turn to a more detailed discussion of the Christian response to evil and to God’s response to evil.