I spoke at church this morning on the theme 'do not repay evil with evil' from Romans 12:17,21. Jesus said 'bless those who curse you' and Paul echoes this with 'bless those who persecute you; bless and do not curse'. Both Jesus and Paul seem to agree on this 'turn the other cheek' strategy. We can all be too easily sucked into the spiral of violence that is reflected in the OT idiom 'an eye for an eye' but the Christian response is strikingly different.
I believe that Christians must always be non-violent in their responses. That doesn't mean that we passively accept injustice, but it does mean that we do not try to match or escalate violence by any means.