I want to beat up a man that attacked my sister.
Why do you want to beat up this man?
Because my sister was injured after he attacked her.
I understand how angry you must be be violence is not the proper response. Report this man to the police and have them deal with the situation. Getting involved in a physical fight with him will not solve your issues.
You are right. Violence is not the best way to solve the problems of the world. I will calm down and talk to the guy.
I am glad to hear that. I would never stoop to someone else's level of abuse even if it is a different kind of violence. Maybe you could teach him a lesson but it is still not moral.