True. But again, when it says "love your enemies" it means pray for them, not that you must allow your enemies to bash your brains out. Just sayin....
The principle of self defense, and more importantly, defense of others is Biblical. In fact, I haven't really studied it that way, but I would suppose the defense of others to be more-or-less commanded, as is the defense of hearth and home (your child, your wife, etc).
But it gets a little gray with defense of self. I am a great big guy, and for most of my life, I translated the 'turn the other cheek' thing pretty literally - I have always been fairly peaceable, never starting violence, And it cost me little in a fight to turn the other cheek... And then I'd crush em like a bug.
As sometimes happens with men, one of my very good friends bears my mark on his face. When I rearranged it for him, we were not friends - That happened at a later time, when I jumped in to help him when several guys were giving him the boots...
I don't say it much, and I know he's forgiven it... But I cannot look at him without a twinge of regret. I really wrecked him. And that brings to mind all the others.