"And they shall sell the live ox and divide its money" (Exodus 21:35). It was stated regarding half damages: Rav Papa said half damages is monetary compensation. Rav Huna the son of Rav Yehoshua said it is a fine. Rav Papa said it is monetary compensation, for he holds that ordinary oxen are not presumed to be guarded, and by strict law the owner should pay the whole, and it was the Merciful One who had mercy upon him because his ox had not yet been forewarned. And Rav Huna the son of Rav Yehoshua said half damages is a fine, for he holds that ordinary oxen are presumed to be guarded, and by strict law he should not pay at all, and it was the Merciful One who fined him so that he would guard his ox. And the law is that half damages is a fine. A refutation followed, and yet it is the law. What is the reason it was refuted yet remains the law? Because it does not list it, and so forth - the matter is not clear-cut to him, since there is half damages for pebbles, which is a fine established by tradition that is monetary, so he neither states it cleanly nor includes it. Now that you have said half damages is a fine, this dog that ate lambs and this cat that ate chickens is an abnormal act, and we do not collect for it in Babylonia. And this applies to large ones, but small ones are its normal way. And if the injured party seized payment, we do not take it from him. And if he summoned the offender to the Land of Israel, we summon him; and if he does not go, we place him under a ban. In either case we place him under a ban until he removes his harmful thing, in line with Rabbi Nathan, as it was taught: Rabbi Nathan says, from where do we learn that a person should not raise a vicious dog in his house, nor set up a rickety ladder in his house? Scripture teaches "and you shall not place blood in your house" (Deuteronomy 22:8).
Half Damages as a Fine and the Warning Against a Vicious Dog
Yalkut Shimoni on Torah 341:21
וְמָכְרוּ אֶת הַשּׁוֹר הַחַי וְחָצוּ אֶת כַּסְפּוֹ אִתְּמַר: פַּלְגָא נִזְקָא רַב פַּפָּא אֲמַר: פַּלְגָא נִזְקָא מָמוֹנָא. רַב הוּנָא בְּרֵהּ דְּרַב יְהוֹשֻׁעַ אֲמַר: קְנָסָא. רַב פַּפָּא אֲמַר מָמוֹנָא קָא סְבַר סְתָם שְׁוָרִים לָאו בְּחֶזְקַת שִׁמּוּר קַיְּמִי, וּבְדִין הוּא דִּלְשַׁלֵּם כֻּלֵּהּ וְרַחֲמָנָא הוּא דְּחַס עִלָּוֵהּ מִשּׁוּם דְּאַכַּתִּי לָא אִיַּעַד תּוֹרֵהּ. וְרַב הוּנָא בְּרֵהּ דְּרַב יְהוֹשֻׁעַ אֲמַר פַּלְגָּא נִזְקָא קְנָסָא קָסָבַר סְתָם שְׁוָרִים בְּחֶזְקַת שִׁמּוּר קַיְּמִי, וּבְדִין הוּא דְּלָא לִישַׁלֵּם כְּלָל וְרַחֲמָנָא הוּא דְּקַנְסֵהּ כִּי הֵיכִי דְּלִנְטְרֵהּ לְתוֹרֵהּ וְכוּ'. וְהִלְכְתָא פַּלְגָּא נִזְקָא קְנָסָא. תְּוֻבְתָּא וְהִלְכָתָא, טַעְמָא מַאי אִתּוֹתַב, מִשּׁוּם דְּלָא קָתָנֵי כו', לָא פְּסִיקָא לֵהּ, כֵּיוָן דְּאִכָּא חֲצִי נֶזֶק צְרוֹרוֹת דְּהִלְכְתָא גְּמִירֵי לַהּ דְּמָמוֹנָא הוּא לָא פָּסֵיק וְלָא קָתָנֵי לַהּ. הַשְׁתָּא דְּאָמַרַת פַּלְגָּא נִזְקָא קְנָסָא, הַאי כַּלְבָּא דַּאֲכַל אִמְּרֵי וְשׁוּנְרָא דַּאֲכַל תַּרְנְגוֹלֵי מְשֻׁנֶּה הוּא וְלָא מַגְבִּינָן לֵהּ בְּבָבֶל. וְהָנֵי מִלֵּי רַבְרְבֵי, אֲבָל זוּטְרֵי אוֹרְחֵהּ הוּא. וְאִי תְּפַס לָא מַפְקִינָן מִנֵּהּ. וְאִי אַזְמְנֵהּ נִיהֲלֵהּ לְאֶרֶץ יִשְׂרָאֵל מַזְמְנִינָן לֵהּ, וְאִי לָא אָזֵיל מְשַׁמְּתִינַן לֵהּ. בֵּין כָּךְ וּבֵין כָּךְ מְשַׁמְּתִינַן לֵהּ דִּלְסַלֵּק הֶזֵּיקֵהּ מִדְּרַבִּי נָתָן, דְּתַנְיָא: רַבִּי נָתָן אוֹמֵר: מִנַּיִן שֶׁלֹּא יְגַדֵּל אָדָם כֶּלֶב רַע בְּתוֹךְ בֵּיתוֹ וְלֹא יַעֲמִיד סֻלָּם רָעוּעַ בְּתוֹךְ בֵּיתוֹ, תַּלְמוּד לוֹמַר: "וְלֹא תָשִׂים דָּמִים בְּבֵיתֶךָ".