Exile

אם יש לאדם תלמידים יעסוק בתקנתם. וכך, רב אחד טוב בעיר ויש תלמידים טובים
כתלמידיו, יעסוק בתקנתם כמו בתקנת תלמידיו. ואם יש לו תוספות ואין לרב אחר
תוספות,
לא יאמר לא אשאיל לו ויבאו תלמידיו לפני ללמוד. לכך אומר 'יהי כבוד
חבירך חביב עליך
כשלך', וכתיב 'ואהבת לרעך כמוך'.
ספר חסידים, מהד'
ויסטנצקי, סימן תתתרעח, עמ' 358

If a person has students, he should concern himself with their
edification. If there is a good teacher in the town, and good students who are
not his own, he should labour over their education as if they were his own
students. And if he has Tosafot and another teacher does not, he should
not say "I will not lend them to him and all his students will come to me".
Therefore it says "the honour of your friend should be as dear to you as your
own", and it says "And you shall love your friend as yourself".

Sefer Hassidim, Wistenzki edition, no. 1478

This, apparently, is the source for the assumption that Talmudic students in the Middle Ages would choose their teacher based on the library the teacher owned. See Israel Ta-Shema, Ritual, Custom and Reality in Franco-Germany, p. 128; Mordechai Breuer, 'The Wandering of Students and Scholars', Culture and Society in Medieval Jewry, Jerusalem 1989, p. 450, n. 21.

There may be a hidden dimension here - the first source quoted is apparently a reference to Avot 4:12. 'R Elazar says - The honour of your student should be as dear to you as the honour of your friend'. 4:14 quotes R Nehorai - 'Exile yourself to the place of Torah'.

Anyway, that's what I'm doing. Going off into exile Thursday morning, to the great libraries of New York City. I hope to continue blogging while I am there. I hope to find plenty to write about.