Chinese term (edited): �鶯���ж������ԏ����

在心为志, 发言为诗, 情动于中,而形于言
from 詩經
(original message is Japanese encoding)

You'd better quote an official English translation for this, like Waley or other scholars. I do not have them on hand, sorry.
A few references from the web follow.

Poetry (shi) is where intent (zhi) goes. In the heart, it is an intent; released through words, it is a poem (shi).
http://academic.reed.edu/chinese/chin-hum/materials/shijing/...

In the heart it is intent; sent forth as speech, it is poetry. Feeling is moved inwardly and takes form in speech.
http://chinesestudies.tripod.com/poetics/zoerensaussy.pdf

The motion is moved in the heart and takes shape in words;
http://www.chinaknowledge.de/Literature/Classics/shijing.htm