Sanhedrin 65B

מתיב רבי זירא: יצאו עדים זוממין, שאין בהן מעשה. ואמאי? הא ליתנהו בלב!

R' Zeira raises an objection to Rava’s answer, as it is stated in a baraita that one who unwittingly commits a transgression punishable by death is obligated to bring a sin-offering, excluding conspiring witnesses, who are not obligated to bring a sin-offering, as their transgressions do not involve an action. R' Zeira asks: And why is a false witness’s testimony not considered a transgression that involves an action? The testimony is delivered through speech, which should be considered an action, as this is not a transgression that is committed in the heart; the witnesses are liable for what they said, and not for their intention.

אמר רבא: שאני עדים זוממין, הואיל וישנו בקול.

Rava says: Conspiring witnesses are different, since their transgression is committed through their voice. The essence of their transgression is not speech itself but rather making themselves heard by the court. Therefore, since the projection of one’s voice does not involve action, the transgression of conspiring witnesses is considered not to be involving action.

וקול, לרבי יוחנן, לאו מעשה הוא? והא איתמר: חסמה בקול והנהיגה בקול, רבי יוחנן אמר: חייב, וריש לקיש אמר: פטור.

The Talmud asks: And is projecting one’s voice not considered an action according to R' Yoḥanan? But wasn’t it stated that amora’im engaged in a dispute concerning the following case: If one muzzled an animal by projecting his voice, by berating it whenever it tried to eat, has he transgressed the prohibition of: “You should not muzzle an ox while it treads out the corn” (Deuteronomy 25:4)? And similarly, if one led different species to work together by projecting his voice, without performing any action, has he transgressed the prohibition of: “You should not plow with an ox and a donkey together” (Deuteronomy 22:10)? R' Yoḥanan says he is liable, and Reish Lakish says he is exempt.