עַל־פִּ֨י הַתּוֹרָ֜ה אֲשֶׁ֣ר יוֹר֗וּךָ וְעַל־הַמִּשְׁפָּ֛ט אֲשֶׁר־יֹאמְר֥וּ לְךָ֖ תַּעֲשֶׂ֑ה לֹ֣א תָס֗וּר מִן־הַדָּבָ֛ר אֲשֶׁר־יַגִּ֥ידֽוּ לְךָ֖ יָמִ֥ין וּשְׂמֹֽאל׃
You shall act in accordance with the instructions given you and the ruling handed down to you; you must not deviate from the verdict that they announce to you either to the right or to the left.
Torah Temimah points to Sanhedrin / Sifrei.
לא תסור. אפילו אומר לך על ימין שהוא שמאל ועל שמאל שהוא ימין.
English: You shall not turn aside — even if they tell you that right is left and left is right.
The classic statement of the duty to obey the high court even when its ruling appears counter-intuitive.
Derash on the verse (Sifrei) — not a formal named middah of the 13. The absolute language is taken as requiring obedience even against one’s own perception.
One must follow the high court’s ruling even when it seems to reverse the plain meaning of right and left.