Bava Metzia 91A

לא שאדם רשאי להמיר, אלא שאם המיר ⁠– מומר, וסופג את הארבעים. אמר ליה: הא מני רבי יהודה היא, דאמר: לאו שאין בו מעשה לוקין עליו.

It is taught at the beginning of tractate Temura that the Torah prohibits the substitution of a non-consecrated animal for a consecrated one. The Mishnah teaches (Temura 2a): That is not to say that it is permitted for a person to effect substitution; rather it means that if one substituted a non-sacred animal for a consecrated animal, the substitution takes effect. The non-sacred animal becomes consecrated, the consecrated animal remains sacred, and the one who substituted the non-sacred animal incurs the 40 lashes. This indicates that one is held liable for mere speech, even without any accompanying action. Reish Lakish said to him: In accordance with whose opinion is this Mishnah? It is in accordance with the opinion of R' Yehuda, who says that one is flogged for violating a prohibition that does not involve an action. By contrast, the dispute between R' Yoḥanan and Reish Lakish is in accordance with the opinion of the Rabbis, who maintain that one is punished only for a transgression that includes a full-fledged action.

ומי מצית מוקמת לה כרבי יהודה? והא קתני רישא: הכל ממירין, אחד האנשים ואחד הנשים, והוינן בה: ״הכל״ לאתויי מאי? לאתויי יורש, ודלא כרבי יהודה,

The Talmud asks: But can you establish and explain that Mishnah in accordance with the opinion of R' Yehuda? After all, it teaches in the first clause: Everyone substitutes a non-sacred animal for a consecrated animal, both men and women. And we discussed this statement by asking the following question: This term: Everyone, serves to add what? What is the tanna including by this phrase? We answered that it serves to add an heir, who can substitute an animal for an animal he inherited that was designated as an offering. And this clause is not in accordance with the opinion of R' Yehuda.