I was listening to the recently released Tim Ferriss podcast with Jack Kornfield, and he told a powerful story that I heard before. I first read it in Heart of the Revolution by Noah Levine.
Long story short, a monk, in a time of hardship, began chanting
Hate cannot drive out hate
but by love alone it is conquered.
This is the ancient truth.
Like I mentioned, very powerful & quick story, and starts about at 1:03:00 in the podcast.