If I recall correctly, this is one the the basic tents of Kyfho, from F. Paul Wislon's outstanding novel, "An Enemy of the State":
Never initiate force against another. That should be the underlying principle of your life. But should someone do violence to you, retaliate without hesitation, without reservation, without quarter, until you are sure that he will never wish to harm - or never be capable of harming - you or yours again.
Something that, apparently, the Israelis once knew... but have since forgotten.