Bava Kamma 41B

היכא דבדק צור ושחט בו ⁠– דעבדיה כעין סקילה, אבל היכא דשחטיה בסכין ⁠– לא!

only in a case where he checked a sharp piece of flint, and, seeing that it did not have any defects, slaughtered the ox with it. In that case, one could say that by slaughtering it with a stone, he performed the equivalent to stoning. Therefore, it is prohibited to eat it. But in a case where he slaughtered it with a knife made of metal, one is not prohibited from eating it.

אמרי: אטו סכין כתיבא באורייתא? והתנן: השוחט במגל יד, בצור ובקנה ⁠– שחיטתו כשירה.

The rabbis said in response: Is that to say that it is written in the Torah that slaughter must performed specifically with a knife, which would justify a distinction between slaughtering with a stone and a knife? But didn’t we learn in the Mishnah (Ḥullin 15b): With regard to one who slaughters with a hand-sickle, with a piece of flint, or with a reed, if these implements were suitable to be used for slaughter, his slaughter is valid?

והשתא דנפקא ליה איסור אכילה ואיסור הנאה מ״לא יאכל את בשרו״, ״בעל השור נקי״ למה לי? להנאת עורו. דסלקא דעתך אמינא: בשרו הוא דאסור בהנאה, עורו נשתרי בהנאה; קמשמע לן ״בעל השור נקי״.

The Talmud asks: And according to R' Abbahu, now that he derives the prohibition of eating and the prohibition of deriving benefit from the verse “Its flesh should not be eaten,” why do I require the statement: “The owner of the ox should be clear”? The Talmud answers: This is stated to prohibit deriving benefit from its hide after it has been killed; as it could enter your mind to say that it is specifically its flesh from which it is prohibited to derive benefit, as the verse states: “Its flesh should not be eaten,” but deriving benefit from its hide will be permitted. Therefore, the Torah teaches us that the owner of the ox should be clear, to indicate it is prohibited to derive benefit from any part of the ox.