Bava Basra 21a
כ"ש דגריס טפי קנאת סופרים תרבה חכמה
The פתחי תשובה חו"מ קנו ס"ק יז quotes from the Sefer יד שאול
about a story that happened the old Melamdim would not allow
the new Melamdim to move into town to take away from them their
He Paskens based on our Gemoro and Shulchan Aruch
"They have no right to stop them from moving into town because
קנאת סופרים תרבה חכמה"
The Chazon Ish ('אמונה ובטחון פרק ג) proves from this case
that Mussar without Halacha can at times be useless.
He explains it as follows.
"A Ba'al Mussar will usually defend the נרדף (underdog) In our casewithout knowing the Halacha people will harass the new Rebbie for
taking away Parnasah from the old Melamed. They will consider
the new Rebbie as the רודף and the Melamed as the נרדף.
Actually, it is the opposite. The new Rebbie is the נרדף
being the Halacha gives him full authority to move in
and take the job for himself and is being harassed for
doing so. The רודף are the supporters of the Melamed
who harass the new Rebbie.
One must know the Halacha not to confuse the נרדף
for the רודף