Confucius. Book 3, Chapter 23.
Book 3, Pa Yih.
The Master instructing the Grand music master of Lu said, "How to play music may be known. At the commencement of the piece, all the parts should stand together. As it proceeds, they should be in harmony while severally distinct and flowing without break, and thus on to the conclusion."
Text source: Lun Yu, The Confucian Analects. Translated by James Legge.