I recently listened to a really good sermon by R.C. Sproul called Behave Like a Christian (Part 2)  that T.Cassle brought to my attention.  Many times when Christians are involved in a conflict with someone we resort to handling things like we would if we were still in our sin in the world.  However we should be handling ourselves like Christ.  Sometimes it’s not that easy to let go and let God handle things.  When people say things about us that are untrue and slanderous we must let God handle them.  He will not let these kind of things slide by without dealing with it,  but will handle them in his own perfect way.

I must say though if someone is threatening you or harming you physically don’t hesitate to involve the proper authorities because when someone does that they are breaking the law and we must not allow anyone to threaten us with bodily harm or hurt us physically.  It is not un-Christian to call the police in these kind of circumstances.
And keep in mind when someone lies about you and spreads untrue things God knows they have lied, God knows everything.  So it doesn’t really matter what people say about you because God knows the truth about you and He is all that really matters anyway.  And pray for those people that slander and spread rumors and lies, pray that God would have mercy on their souls.