Standing for Aseres HaDibros: The Rambam's View

Teshuva 263 (Blau pp. 495-499)

The Rambam was asked about a community where the custom was to sit during the reading of the Aseres HaDibros. A new Rav that came there stood and everyone followed him. The one who raised the question felt that this contradicted the gemara in Berakhos 12a that eliminated the daily reading of the Aseres HaDibros because it gave credence to the minim (i.e. Christians?)who believed that the Ten Commandments are more important than the rest of the Torah. The custom of standing appeared Christian-like and provided ammunition to the Christians when they debated with Jews. Additionally, what is the halakha concerning customs and their precedence in a case like this?

The Rambam answered that sitting is correct and that it does not matter what the custom is in Baghdad or anywhere else. The definition of a min is anyone who does not believe in one the principles of the Torah i.e. that the Torah is divinely revealed (Sanhedrin 99a). There is no difference between someone who denies the entire Torah or one pasuk and says Moshe said this on his own. There are minim who believe that only the Ten Commandments are divinely revealed. For this reason Chazal prohibited the daily reading of the Aseres HaDibros in davening.