תלמוד על אבות 5:10

Hillel the Elder presented seven interpretive principles before the House of Beteira: kal vahomer (an a fortiori inference: if so for a lenient case, all the more so for a stringent case), gezeira shava (similar principle learned from linking words), binyan av (building on a primary category), miklal u’frat (specific cases limiting the general rule), miprat u’klal (a generalization expanding the application of a specific case), kayotzei bo bemakom akher (a similar case in another place), and davar halamed minyano (a principle learned out from context); these are the seven interpretive principles that Hillel the Elder presented before the House of Beteira.

There are four types of people. The one who says: What’s mine is yours, and what’s yours is mine, etc.
There are four types of students: One who wants to learn and to teach others, he is looked on favorably. One who wants to learn but not to teach others, he is looked on unfavorably. One who wants to teach others but not to learn, he has a mediocre character (and some say he has the character of someone from Sodom). One who wants neither to learn nor to teach others, this is a completely wicked person.
There are four types of people in the study hall: One who approaches others and sits down with them to learn, he has share in the learning. One who approaches others but does not sit down with them, he has no share in the learning. One who keeps his distance from others but still sits down with them to learn, he has share in the learning. One who keeps his distance from others and [likewise] does not sit down with them, he has no share in the learning.