“When bad people are doing bad things to good people, good people have an obligation to engage in conflict with them. When bad people try to hurt you, you have an obligation to engage in conflict with them. 

Conflict can be one of our highest moral duties.

No matter who you are, where you live, and what you do, some form of conflict is inevitable. This presents you with a choice: either you can just wing it when conflict occurs, or you can prepare for conflict and become more skilled at handling it. Only one of these choices is intelligent.”

– The Gift of Violence, page 233

You can order your copy here: https://www.amazon.com/Gift-Violence-Practical-Knowledge-Surviving/dp/1634312309/