To those whose talents are above mediocrity, the highest subjects may be announced. To those who are below mediocrity, the highest subjects may not be announced.
中人以上，可以语上也；中人以下，不可以语上也。
Source: The Analects, Yong Ye VI, Chapter 21
Author: Confucius
The Principle of Pedagogical Suitability: Teaching According to the Student’s Capacity
