The Master said, "In teaching there should be no distinction of classes."
子曰、有教、無類。
Analects 15.39
The same idea in other traditions
Contemplate and reflect upon knowledge, and you will become a benefactor to others.
Give instruction to a wise man, and he will be yet wiser: teach a just man, and he will increase in learning.
Therefore, seeker after the highest truth, study the sacred lore, in order to cause yourself and others to attain perfection.
By (the Token of) Time (through the ages), Verily Man is in loss, Except such as have Faith, and do righteous deeds, and (join together) in the mutual teaching of Truth, and of Patience and Constancy.
Jehoshua' ben Perachia and Matthai the Arbelite received from them. Jehoshua' ben Perachiah said, Make unto thyself a master; and possess thyself of an associate; and judge every man in the scale of merit.
If you see an intelligent man who tells you where true treasures are to be found, who shows what is to be avoided, and administers reproofs, follow that wise man; it will be better, not worse, for those who follow him. Let him admonish, let him teach, let him forbid what is improper!--he will be beloved of the good, by the bad he will be hated.
After having taught the Veda, the teacher instructs the pupil: 'Say what is true! Do thy duty! Do not neglect the study of the Veda! After having brought to thy teacher his proper reward, do not cut off the line of children! Do not swerve from the truth! Do not swerve from duty! Do not neglect what is useful! Do not neglect greatness! Do not neglect the learning and teaching of the Veda!