In Parshat Ki Tisa, after describing the horrific events of the Chet HaEigel, the Torah states (32:28), “And there fell from the people on that day about three thousand men.” The Torah indicates that just 3,000 men participated in the sin of the Cheit HaEigel, a mere .5% of the people in a nation of 600,000 men. Even so, Chazal tell us that all of the misfortunes that befell Klal Yisrael for the rest of Jewish history stemmed in part from this sin (see Rashi to Shemot 32:34). Furthermore, after seeing the Eigel HaZahav that Bnei Yisrael built, Moshe Rabbeinu immediately shattered the Luchot. This is shocking, as so few of the Jewish people actually participated in this terrible sin. Why were these Luchot, which were actually carved and written by Hashem, and which were perhaps the holiest item that the Jewish people have ever received, destroyed for the sin of just a relatively small group of people?
To answer this question I would like to cite the words of Rabbi Chaim Jachter in one of his Shiurim at TABC. In relation to a different topic in Chumash (the Ir Hanidachat), Rabbi Jachter explained that tolerance is equivalent to acceptance. Even though just a few members of Klal Yisrael actually participated in this great Aveirah, because everyone else accepted what they were doing and did not stand up for Hashem or try to stop these Aveirot, everyone was punished along with the actual sinners.
We learn from this that if one sees an Aveirah occurring before him, he cannot just let it go or say, “I am not doing the Aveirah, so why should I bother myself with those who are?” If we see others speaking Lashon Hara or performing any other Aveirah, big or small, we must stand up for Hashem and the Mitzvot. We must follow the Torah’s command of “Hochei’ach Tochiach Et Amitecha” (Vayikra 19:17), correcting a fellow Jew who sins.
--Adapted from a Dvar Torah in Thinking Outside the Box