The Avos D'rav Nosson-Perek Chaf Vav
says why some Torah Scholars die young, it's not because of their sins however it's only because they stop learning and get involved in shmoozing.
It is explained from the words of the Rishonim, that it's a Prohibition to shmooze, as it says in
Shema V'debata Bam "and you shall
speak in them" which is interpeted to mean: in them you are able to speak (Torah), and not in other things
(Shmooze). Rabbeinu Chananel explains "Bam" in them. If the time comes to say Krias Shema and you are learning
- you can stop learning, but not for anything else. The reason for the Eisor
is mentioned in Rabbeinu Yona, Pirchei Avos Perek Gimmel: The Eisor because
of Kavod Hatorah and a lack of Kavod Hatorah equals a lack of Kavod Hashem.