Bava Kamma 28A

עמך?! בן בג בג יחידאה הוא, ופליגי רבנן עליה.

You can keep this question to yourself, as it poses no difficulty at all. Ben Bag Bag states an individual opinion in this regard, and the Rabbis disagree with him.

רבי ינאי אמר: מאי ״שבור את שיניו״⁠ – בדין.

R' Yannai says an alternative response to Rav Kahana’s objection: What does the baraita mean by the phrase: Break his teeth? It means sue him in judgment.

אי הכי, ״ואמור לו״?! ״ואומרים לו״ מיבעי ליה! ״שלי אני נוטל״?! ״שלו הוא נוטל״ מיבעי ליה! קשיא.

The Talmud asks: If so, the subsequent statement in the baraita: And say to him, is inaccurate. It should have stated: And they, the court, say to him. Likewise, the wording: I am taking what is mine, is inaccurate. Since it is the court who makes this statement, the baraita should have stated: He is taking what is his. The Talmud concludes: Indeed, this poses a difficulty for Rav Yehuda’s version of the response.

תא שמע: שור שעלה על גבי חבירו להורגו, ובא בעל התחתון ושמט את שלו, ונפל עליון ומת ⁠– פטור. מאי, לאו במועד ⁠– דליכא פסידא?

The Talmud suggests: Come and hear an alternative proof for Rav Naḥman’s opinion. It is stated in a baraita: With regard to an ox that climbed on the back of another ox to kill it, and the owner of the ox on the bottom came and removed his ox, and the ox on top consequently fell and died, the owner of the ox on the bottom is exempt from paying for the dead ox. What, is this ruling not stated with regard to a case where the attacker is a forewarned ox, where there is no loss to the owner of the bottom ox, since even if the owner of the ox on the bottom does not remove his ox, he will eventually receive full restitution from the owner of the belligerent ox? Yet he is exempt from paying restitution for causing the death of the belligerent ox. Evidently, he had the right to take justice into his own hands.