As someone who is an advocate for self-defense, and therefore carrying arms, I am obliged to think about self-defense and when it's appropriate and when it's not.
Certainly, it makes sense for anyone who carries arms for self-defense to think about these things before they are in a situation where quick action is needed. You can't call time-out to sort out your thoughts on self-defense. You need to already have though about what you are willing to do, or not do.
To avoid thought on this topic is in itself poor preparedness, as having the right mindset is a significant part of self-defense, as much as being armed.
In that regard, one source of thought that I turn to (among others) is the Bible. I was having a back-and-forth over at Brad's Bar and Grill about self-defense and someone brought up the admonition in the Sermon on the Mount to "turn the other cheek". I see that admonition as not resorting to violence in the face of an insult or a rebuke. Simply being insulted is not grounds for violence. If you're insulted, simply allow that person to insult you again.
As I see it, an insult or a slap in the face is not the same as a serious attack on your life. Accordingly, I don't agree with the old ethics of having a duel to defend your honor like they had back in the Napoleonic Era. Dueling for honor isn't something that I would have participated in. You simply turn the other cheek.
At a later point, Brad brought up the question of what Jesus would the say about Good Samaritan, if he had encountered the robbers in the act. Should the Good Samaritan have intervened, or should he have waited and then helped the man. Apparently, someone thought this was a difficult question. It's not. You help people. Need some controlling authority?
Psalm 82:4 "Rescue the weak and the needy; Deliver them from the hand of the wicked."
However, I don't think we mere mortals should get too carried away with ourselves. Having the means to defend yourself does not necessarily make you all-powerful. Don't trust your tools too much. At the end of the day, you have to realize that you're not in control. Even David, before he killed Goliath said:
“All those gathered here will know that it is not by sword or spear that the Lord saves; for the battle is the Lord’s, and he will give all of you into our hands.”
My thoughts on self-defense put these two passages from the Bible together. Do what you can to protect the weak and the needy, but realize that you’re not in control of everything. Don’t trust yourself and your arms to the exclusion of God and his plan.
Your mileage may vary.