The Midrash Lekach Tov on Parshas Shlach tells us a new Halacha which is not commonly practiced. When Moshe and Aharon heard the claims of the spies, the passuk says that they ripped their clothing in mourning. The Midrash comments that from here we learn that one must tear his clothing upon seeing people throwing off the yoke of Torah and mitzvos. Being that this halachah is seldom practiced, everyone should ask their Rov in reference to its guidelines applications.

Rabbi Aharon Dovid Singer
Rosh Kollel, NMB Kollel