If you are going to deal in death, you should be willing to see the truth of it, not some glorious lie. If I have a battle with another sword player, it is between the two of us, our business, our truth. But if you run a planet and you get pissed off at somebody the next orbit over, you each might send a million soldiers to recycling plants. A smart rocket can come from a thousand klicks away to kill you; it doesn't care and it won't be in the least upset that it has blasted you to atomic debris. That's the real horror of modern war, that it is impersonal. Being cut with a sword hurts, and if you are close enough to do it, you can't miss the other's pain.
Habit must play a larger place in our religious life. We worship when we feel like it, we pray when we feel like it. We read the Bible when we feel like it. Leaving our religious exercises to the promptings of impulse, we become creatures of impulse rather than soldiers of Christ. An army made up of creatures of impulse would be only a mob. So is a church.