Mishná sobre Números 12:20

Rabbi Elazar ben Shammua said: let the honor of your student be as dear to you as your own, and the honor of your colleague as the reverence for your teacher, and the reverence for your teacher as the reverence of heaven.

[There are] seven things [characteristic] in a clod, and seven in a wise man: A wise man does not speak before one who is greater than he in wisdom, And does not break into his fellow’s speech; And is not hasty to answer; He asks what is relevant, and he answers to the point; And he speaks of the first [point] first, and of the last [point] last; And concerning that which he has not heard, he says: I have not heard; And he acknowledges the truth. And the reverse of these [are characteristic] in a clod.

If a person who was clean put his head and the greater part of his body inside an unclean house, he becomes unclean. And if an unclean man put his head and the greater part of his body inside a clean house he causes it to be unclean. If he put three fingerbreadths square of a clean cloak into an unclean house, the cloak becomes unclean; And if he put even the size of an olive of an unclean [cloak] into a clean house, the house becomes unclean.