Speak to the entire community of Bnei Yisroel and you shall tell them – you should be holy for I, Hashem your G-d, am holy
Rashi writes that this Parsha was to be said in public because it includes most of the important rules of the Torah. The Mizrachi adds an explanation for the uniqueness of this Parsha. The truth is, Moshe Rabbeinu also taught all other Parshiyos and Mitzvos to the entire community, as we see in the Gemara in Eiruvin. However, this case was different. When teaching all other Mitzvos, Klal Yisroel came in groups to hear the command from Moshe's mouth. When teaching this Parsha, they came all at once.
The Gemara in Eiruvin (54b) says, how did Moshe teach Torah to Klal Yisroel? Moshe Rabbeinu heard the Halacha from Hashem. Then, Aaron entered, and Moshe taught him what he had heard from Hashem. Aharon then went and sat at Moshe Rabbeinu’s side, and his children entered. They listened to Moshe repeating the shiur, whereupon they moved to sit on either side of Moshe Rabbeinu. Then, the elders of Klal Yisroel came, and Moshe repeated the Shiur a third time. After that, the entire Klal Yisroel entered, and Moshe taught them the Halachos for the fourth time. Now, Aaron had heard the Halacha four times, his children had only heard it three times, the elders of Klal Yisroel heard it twice, and the rest of the nation heard it once from the mouth of Moshe Rabbeinu. Then, Moshe departed, and Aharon repeated the Halacha to the assembled. He also left them and gave over the job to his children, who taught them again until the entire Klal Yisroel had heard it four times. The Mizrachi says that this Parsha of Kedoshim was different, because all of them came at once to hear the Parsha from Moshe Rabbeinu.
The Ohr Hachaim is unsure about the intent of the Mizrachi. Does the Mizrachi mean that Klal Yisroel itself, when arriving for Moshe Rabbeinu's final repeating, was divided into groups? If so, Moshe Rabbeinu repeated the Halacha more than four times, but the Gemara writes that it was only four. The only possibility is that this time, Moshe did not separate his brother, his brother’s children, and the elders of Klal Yisroel from the rest of Klal Yisroel; rather, he taught them all at once.
The Ohr Hachaim explains the reason behind Moshe’s method of teaching. Why did Moshe not call the entire congregation at once and teach them all the Halacha four times? Why did he divide them like he did? Why was it better for them to hear it once from him and then again from Aharon etc.?
The Ohr Hachaim offers two explanations. Either the reason was to show honor to the various levels of leaders in Klal Yisroel, each one in its place in the hierarchy. The other reason is to ensure the Halacha is accurately repeated. If Moshe would have repeated it four times, Klal Yisroel could not be sure that Aharon and his sons had heard it accurately, and there was a possibility of a distortion in the transmission of the Torah. Now, with Aharon repeating the Halacha, the listeners could compare his repetition with that of Moshe Rabbeinu, and no mistakes would be allowed through. The need for absolute accuracy in the tradition of Torah shebaal Peh caused them to use multiple levels of protection to ensure total purity.
However, both of these reasons fail to explain why this parsha should be different. Why should the Parsha with the important Mitzvos be treated any differently? Do Aharon, his sons, and the elders of Klal Yisroel not deserve any honor here? Are we less afraid of distortions creeping into the transmission of the oral Torah? On the contrary, we should be more worried about distortions when the laws are that central to the Torah.
The Ohr Hachaim explains the difference between this Parsha and all other Parshiyos in a different way to the Mizrachi. He explains that when Moshe taught the Torah to Klal Yisroel, he only taught the men. In Parshas, Kedoshim, Moshe taught the Torah in the same fashion as all other Parshiyos, with Aharon preceding his sons, etc. But when Klal Yisroel came to hear the Mitzvos, they were told to come with their wives and children, just like at the Maamad Har Sinai, where nobody stayed behind.
