The Golden Rule is found throughout the world, throughout the ages, and in virtually every religion. Unfortunately, very few religious practitioners actually make this philosophy an active part of their daily lives.
The warrior should make the Golden Rule a part of his life, that is, until he has no other choice.
As John Wayne's character in the Shootist stated,
"I don't do these things to other people, and I require the same from them."
There is a time and a place for the Golden Rule, and a time and a place for regrettably harsher lessons.