It is "New" because it is different from the older rule about "an eye for an eye and a tooth for a tooth." Instead of inflicting pain on another person who did the same thing to you, we can show him/her our love and forgiveness.
Loving responses to aggression create a big difference. I've seen it work many times before. Fire cannot be 'doused' with fire. Only love can erase fear that causes plenty of aggression.
It really works.