Here's a brief collection of quotes, I'd be glad to know of more.
Rabbi Yitzchok Etshalom Talmud Torah 5:13
13. The students add to the teacher's wisdom and expand his understanding. The sages said: I have learned much wisdom from my teacher, more from my colleagues and the most from my students (BT Ta'anit 7a); and just as a small piece of wood ignites a large one, similarly a small student sharpens the teacher['s mind] until he extracts from him, through his questions, wondrous wisdom.
alternate translation, from Maimonides, Laws of Torah Study, http://www.panix.com/~jjbaker/MadaTT.html chapt 5:
13) Students add to the wisdom of their Rabbi, and open his heart. The Sages said that they learnt more from their Rabbis than from their friends, but learnt even more from their students. Just as a small candle can light a big one so a student sharpens his Rabbi's wits, by extracting from him his wisdom by means of questions.
Pirkei avot: Chapter 1.1
The Men of the Great Assembly had three sayings:
Be deliberate in judging;
Educate many students;
Make a fence around the Torah.
Some commentaries have trouble with the first two clauses, and I've seen "get a friend" translated as "find someone to study with." But another way to understand it (maybe, I'm no Talmud scholar) is that teachers and friends (and students and friends) can intersect and be the same folks...
"דאמר רב יוסי בר חוני בכל אדם מתקנא חוץ מבנו ותלמידו" "Reb Yossi bar Honi said 'of everyone a man is envious except his son and his student'."
( סנהדרין • קה ב )
update: I should note that another literature/tradition in which bonds between teachers and students are noted is in martial arts .