Mencius - Book 1, Part 2, Chapter 3A

The king Hsüan of Ch'î 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'âi served the Hsün-yü, and Kâu-ch'ien served Wû.

'He who with a 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 kingdom. He who stands in awe of Heaven, will affect with his love and protection his own kingdom.

'It is said in the Book of Poetry, "I fear the Majesty of Heaven, and will thus preserve its favoring decree."'

The king said,'A great saying! But I have an infirmity; I love valor.'

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.
~ James Legge translation via nothingistic.org ~

Go here to read the introductory post to this serialized version of the Works of Mencius.