Mencius. Book 1, Part 2, Chapter 3.
1. The King Seuen of Ts'e asked, saying, "Is there any way to regulate one's maintenance of intercourse with neighboring kingdoms?" Mencius replied, "There is. But it requires a perfectly virtuous prince to be able, with a great country, to serve a small one; as, for instance, T'ang served Ko, and King Wan served the Kwan barbarians. And it requires a wise prince to be able, with a small country, to serve a large one; as the King T'ae served the Heun-yuh, and Kow-tseen served Woo.
2. "He who with a great state serves a small one, delights in Heaven. He who with a small state serves a large one, stands in awe of Heaven. He who delights in Heaven, will affect with his love and protection the whole empire. He who stands in awe of Heaven, will affect with his love and protection his own kingdom.
3. "It is said in the 'Book of Poetry,' 'I fear the majesty of Heaven, and will thus preserve its favoring decree.' "
4. The king said, "A great saying! But I have an infirmity; I love valor."
5. "I beg Your Majesty," was the reply, "not to love small valor. If a man brandishes his sword, looks fiercely, and says, 'How dare he withstand me?' ‹ this is the valor of a common man, who can be the opponent only of a single individual. I beg Your Majesty to greaten it.
6. "It is said in the 'Book of Poetry,'
'The king blazed with anger,
And he marshaled his hosts,
To stop the march to Keu,
To consolidate the prosperity of Chow,
To meet the expectations of the empire.
This was the valor of King Wan. King Wan, in one burst of his anger, gave repose to all the people of the empire.
7. "In the 'Book of History' it is said, 'Heaven, having produced the inferior people, appointed for them rulers and teachers, with the purpose that they should be assisting to God, and therefore distinguished them throughout the four quarters of the empire. Whoever are offenders, and whoever are innocent, here am I to deal with them. How dare any under heaven give indulgence to their refractory wills?' There was one man pursuing a violent and disorderly course in the empire, and King Woo was ashamed of it. This was the valor of King Woo. He also, by one display of his anger, gave repose to all the people of the empire.
8. "Let now Your Majesty also, in one burst of anger, give repose to all the people of the empire. The people are only afraid that Your Majesty does not love valor."
Text source: The Works of Mencius. Translated by James Legge.