The Torah admonishes us to follow the teachings of the Rabbis by saying: לֹא תָסוּר מִן הַדָּבָר אֲשֶׁר יַגִּידוּ לְךָ יָמִין וּשְׂמֹאל, “…you shall not deviate from the word that they will tell you, right or left.” (Deut. 17,11)
It is generally accepted to mean that if one breaches the law, a Mitzvah or a prohibition of the Rabbis of the Talmud, he is guilty of transgressing this Biblical decree. Rabbi Soloveitchik directed our attention to the commentary of the Ramban, or Nachmonides, an early recognized Rabbinic scholar, who says otherwise.
The Ramban points out that if one does not follow the dictates of the Rabbis, and does indeed transgress a regulation of the Rabbis, he is not in violation of this Torah law. One violates this commandment when he rejects the general principle of Rabbinic Law, that is, he rejects the Oral Law.
Throughout the ages there have been groups who felt that the Rabbinic interpretations of the Torah were not binding and their decrees were not obligatory. This, according the Ramban, is the real transgression of this Biblical edict.