In fact, there are opinions out there on what "it is enough" would have actually meant when Jesus said it. For Luke Timothy Johnson (1991), "it is enough" essentially carries the same meaning as "enough of this nonsense" and he comes to that conclusion by matching it grammatically and in its original language to something Jesus says later surrounding this same issue, which we'll now get into.
At the end of the day, I understand that we may possess a different view on self-defense. However, I think we can agree that scripture has been used for terrible reasons before and a little look at the context of a verse can truly help us steer clear of poor interpretations. So, I hope that you have gotten something out of this discussion. Grace and peace to you all!
Sprinkle, Preston. Fight: A Christian Case for Nonviolence. Colorado Springs, CO: David C. Cook, 2013. Print.