Emerson Quote

I'm reading The Power of Nonviolence, a birthday present from skp. Sometimes I don't realize how much the news wears on me. Reading a book like this helps put things in perspective and gives me hope. Here's a quote from Ralph Waldo Emerson's essay War:
"War and peace thus resolve themselves into a mercury of the state of cultivation. At a certain stage of his progress, the man fights, if he be of a sound body and mind. At a certain higher stage he makes no offensive demonstration, but is alert to repel injury, and of an unconquerable heart. At a still higher stage he comes into the region of holiness; passion has passed away from him; his warlike nature is all converted into an active medicinal principle; he sacrifices himself, and accepts with alacrity wearisome tasks of denial and charity; but, being attacked, he bears it and turns the other cheek, as one engaged, throughout his being, no longer to the service of an individual but to the common soul of all men."
I can't stop thinking about this paragraph since I've read it. It's counter-intuitive at first glance. And definitely counter to current world events. What does it mean to evolve?