This article relates that Rabbi Yechezkel Halberstam, the Shinnover Rebbe, responded to a statement written in the in 1891 published sefer "Shivas Tzion" written by Rabbi Avraham Yaakov Slutzky.
The article goes on to say that:
in the introduction to his book, he quoted the Haflaah as saying that for a person who lives in Eretz Yisroel, keeping Torah and mitzvos is not as important as it is for one who lives in other lands.
The Shinnover Rebbe, to this, responded to another rav that:
“On the contrary, Hashem is stricter on those who live in Eretz Yisroel, as it says, ‘Let the land not vomit you out…’ For Eretz Yisroel can tolerate only pure individuals…”
I haven't been able to locate neither this sefer nor the reaction itself in משכנות הרועים. Where can all this be found?
Edit: the sefer Mishkenos Haro'im is written by Rabbi Aaron Rosenberg. I haven't found this sefer online. Is it online?
I have found that it was written in 1983-84 by Rabbi Rosenberg (New York) and it is a compilation of sources.