I've had some questions about the context of the quote at the top of the page. Here's the full statement:
"The Art of Peace is medicine for a sick world. There is evil and disorder in the world because people have forgotten that all things emanate from one source. Return to that source and leave behind all self-centered thoughts, petty desires, and anger. Those who are possessed by nothing possess everything."
- Excerpted by William McLuskie from The Art of Peace a collection of quotes by Morihei Ueshiba translated by John Stevens.
The idea that " all things emanate from one source" appears to be the crux of the idea. This concept is very familiar in Eastern philosophies. Scholars may quibble, but the idea exists in Shinto, Buddhism and Taoism, for sure.
But what is that source? Simply, the source is you. If the universe if infinite, every point is the center, so your "center" might as well be, too.
It's with that realization that we can "return to that source and leave behind all self-centered thoughts, petty desires, and anger." If one realized he is the source, he must, at the same time realize that everyone and everything else is also the source. So self-centeredness naturally falls away with such a realization. That's why enlightenment is always expressed in compassion.
I admit that when I practice aikido, I'm not usually thinking about how I'm the center of the universe, but maybe I can try just the center of the circle and work out from there. ;)