Confucius: Universal Education in Chinese / Japanese...

自行束脩以上吾未尝无诲焉 means, for anyone who brings even the smallest token of appreciation, I have yet to refuse instruction.

Another way to put it is: If a student (or potential student) shows just an ounce of interest, desire, or appreciation for the opportunity to learn, a teacher should offer a pound of knowledge.

This quote is from the Analects of Confucius.

This was written over 2500 years ago. The composition is in ancient Chinese grammar and phrasing. A modern Chinese person would need a background in Chinese literature to understand this without the aid of a reference.