In instances where there is a blatant contradiction between the peshat and midrash halakha, Ibn Ezra systematically interprets the verses in accordance with the midrash. However, other commentators, including the Rashbam and the Vilna Gaon, maintain the distinction between peshat and derash – even in matters of halakha.

Rashbam maintained that the principle of polysemy, of multiple valid interpretations of the text, is relevant even in these instances. He emphasizes that the laws derived from seeming superfluities in the text are the “essence” – and by this he would seem to be saying that the midrashic teaching is binding, in practical, halakhic terms, but nevertheless the plain sense of the verse still has its value and role.

Peshat and Halakha
Tefillin
The Definition of the Jewish Day
The Scapegoat
Courtesy of the Virtual Beit Midrash, Yeshivat Har Etzion