Commentary for Bava Kamma 4:8
שׁוֹר שֶׁהוּא יוֹצֵא לְהִסָּקֵל וְהִקְדִּישׁוֹ בְעָלָיו, אֵינוֹ מֻקְדָּשׁ. שְׁחָטוֹ, בְּשָׂרוֹ אָסוּר. וְאִם עַד שֶׁלֹּא נִגְמַר דִּינוֹ הִקְדִּישׁוֹ בְעָלָיו, מֻקְדָּשׁ. וְאִם שְׁחָטוֹ, בְּשָׂרוֹ מֻתָּר:
If an ox were taken out to be stoned, and its owner dedicated it (to the Temple), it is not dedicated. If he slaughtered it, its flesh is forbidden, [it being written (Exodus 21:28): "The ox shall be stoned and its flesh shall not be eaten." From "the ox shall be stoned," do I not know that it is neveilah [carrion], which may not be eaten? Why need it be stated: "and its flesh shall not be eaten"? To teach that if he slaughtered it after its judgment (to be stoned), it is forbidden.] And if before its judgment were pronounced, its owner dedicated it, it is dedicated. [A (practical) difference — If he benefits from it, he is guilty of me'ilah (abuse of sacred property)]. And if he slaughtered it, its flesh is permitted.
Rambam on Mishnah Bava Kamma
Bartenura on Mishnah Bava Kamma
English Explanation of Mishnah Bava Kamma
But if before its sentence was complete its owner dedicated it, it is dedicated. If he slaughtered it, its flesh is permitted.
Mishnah Eight deals with an owner of a goring ox who tried to “cheat the system” by either dedicating the ox to the Temple, and thereby getting credit for a sacrifice, or by ritually slaughtering the ox, and thereby getting food to eat and the leather from the hide. We learned in the aforementioned verses in Exodus that the ox must be executed and its meat is forbidden for use. Our mishnah tells us that this is so only if its sentence has already been pronounced by the court. If it has not, and a person should either dedicate it or slaughter it, the person’s actions are valid and either the Temple or the person himself may derive benefit from the ox.