I have no problem with the sentiment. It's noble. It's good for you. But it isn't a thousand years old. "nations" are a concept that dates back to The Enlightenment, no earlier.
If you search for the quote it's attributed to a 12th century monk about eight times in the past ten years. If you dig a little deeper they try and pin it on Israel Salanter, a 19th century German rabbi. If you dig deeper than that, they attribute it to Israel Salanter, an unknown 11th century monk.
The two wolves is a cool parable, too, even if it came from Billy Graham.