Violence is the intentional use of physical force or power, threatened or actual, against a person, or against a group , with the intention that it results in or has a high likelihood of resulting in injury, death, psychological harm, maldevelopment or deprivation, violence is usually taken when it seems neccassary, to serve a cause that must be served, rarely is violence served on whim.
War is a good example of when violence is used and how violence demonstrates personal goals.War is an organized and often prolonged conflict that is carried out by states and/or non-state actors. It is characterised by extreme violence, social disruption, human suffering, and economic destruction. However in war, violence seems to be more extreme in the sense that the part of violence that is organised, is much more organised in war and the part that is chaos is much more potent in war.
I think that violence is neccassary depending on the circumstancs, if there was a rapist who shows no mercy and will not stop under injury about to rape a woman, and I was there, I would take up arms and defend her, even if it means violence. I think that violence is neccasary, only when neccassary, it can not be applied to every situation and shouldn't be applied to every situation. In the end violence can be the strongest dictator for ideas such as freedom and courage, so it has a purpose