Mishnayos Bava Kamma Perek 2 Mishnah 5

And what is the case of the ox that causes damage while on the property of the injured party, mentioned in an earlier mishna (15b) that listed animals that are forewarned? If the animal gored, pushed, bit, squatted upon, or kicked another animal in the public domain, the owner is liable to pay half the cost of the damage if the ox was innocuous, but if it acted while on the property of the injured party, Rabbi Tarfon says: He must pay the full cost of the damage, and the Rabbis say: He must pay half the cost of the damage, as in any other case classified as Goring. Rabbi Tarfon said to the Rabbis: If in a place where the Torah was lenient with regard to damage classified as Eating and with regard to Trampling, specifically in the public domain, as the owner is exempt from liability, nevertheless the Torah was strict with regard to these forms of damage if they occurred on the property of the injured party, requiring him to pay the full cost of the damage, then in a place where the Torah was strict with regard to cases of damage classified as Goring, specifically in the public domain, requiring the owner liable to pay for half the cost of the damage, is it not right that we should be strict with regard to this form of damage if it occurs on the property of the injured party to likewise require the owner of the animal to pay the full cost of the damage? The Rabbis said to him: Although there is an a fortiori inference being applied here, still it is sufficient for the conclusion that emerges from an a fortiori inference to be like its source, meaning that the halakha cannot be stricter with the inference than it is with the case that serves as the source of the inference. Therefore, just as one is liable to pay half the cost of the damage classified as Goring in the public domain, so too, for damage classified as Goring on the property of the injured party he is liable to pay only half the cost of the damage. Rabbi Tarfon said to them: If that is your opinion, then I as well will not derive an inference with regard to Goring from a different case of Goring. I will instead derive an inference with regard to Goring from Trampling: And if in a place where the Torah was lenient with regard to damage classified as Eating and Trampling, specifically in the public domain, as the owner is exempt from liability, nevertheless the Torah was strict with regard to damage classified as Goring, requiring him to pay half the cost of the damage, then in a place where the Torah was strict with regard to damage classified as Eating and Trampling, specifically on the property of the injured party as the animal’s owner is obligated to pay the full cost of the damage, is it not right that we should be equally strict with regard to damage classified as Goring and require payment of the full cost of the damage in this case as well? The Rabbis said to him: Here as well, it is sufficient for the conclusion that emerges from an a fortiori inference to be like its source, and therefore, just as one is liable to pay half the cost of the damage classified as Goring in the public domain, so too, for damage classified as Goring on the property of the injured party he will be liable to pay only half the cost of the damage, as ultimately your inference still depends on the fact that for Goring in the public domain one pays half the cost of the damage.

שׁוֹר הַמַּזִּיק בִּרְשׁוּת הַנִּזָּק כֵּיצַד. נָגַח, נָגַף, נָשַׁךְ, רָבַץ, בָּעַט, בִּרְשׁוּת הָרַבִּים, מְשַׁלֵּם חֲצִי נֶזֶק. בִּרְשׁוּת הַנִּזָּק, רַבִּי טַרְפוֹן אוֹמֵר נֶזֶק שָׁלֵם, וַחֲכָמִים אוֹמְרִים חֲצִי נֶזֶק. אָמַר לָהֶם רַבִּי טַרְפוֹן, וּמַה בִּמְקוֹם שֶׁהֵקֵל עַל הַשֵּׁן וְעַל הָרֶגֶל בִּרְשׁוּת הָרַבִּים, שֶׁהוּא פָטוּר, הֶחְמִיר עֲלֵיהֶם בִּרְשׁוּת הַנִּזָּק לְשַׁלֵּם נֶזֶק שָׁלֵם, מְקוֹם שֶׁהֶחְמִיר עַל הַקֶּרֶן בִּרְשׁוּת הָרַבִּים, לְשַׁלֵּם חֲצִי נֶזֶק, אֵינוֹ דִין שֶׁנַּחְמִיר עָלֶיהָ בִּרְשׁוּת הַנִּזָּק לְשַׁלֵּם נֶזֶק שָׁלֵם. אָמְרוּ לוֹ, דַּיּוֹ לַבָּא מִן הַדִּין לִהְיוֹת כַּנִּדּוֹן, מַה בִרְשׁוּת הָרַבִּים חֲצִי נֶזֶק, אַף בִּרְשׁוּת הַנִּזָּק חֲצִי נֶזֶק. אָמַר לָהֶם, אֲנִי לֹא אָדוּן קֶרֶן מִקֶּרֶן, אֲנִי אָדוּן קֶרֶן מֵרֶגֶל. וּמַה בִמְקוֹם שֶׁהֵקֵל עַל הַשֵּׁן וְעַל הָרֶגֶל, בִּרְשׁוּת הָרַבִּים, הֶחְמִיר בַּקֶּרֶן, מְקוֹם שֶׁהֶחְמִיר עַל הַשֵּׁן וְעַל הָרֶגֶל, בִּרְשׁוּת הַנִּזָּק, אֵינוֹ דִין שֶׁנַּחְמִיר בַּקֶּרֶן. אָמְרוּ לוֹ, דַּיּוֹ לַבָּא מִן הַדִּין לִהְיוֹת כַּנִּדּוֹן, מַה בִּרְשׁוּת הָרַבִּים חֲצִי נֶזֶק, אַף בִּרְשׁוּת הַנִּזָּק חֲצִי נֶזֶק: