Jerusalem Talmud Bava Kamma 4.9

משנה: מְסָרוֹ לְשׁוֹמֵר חִנָּם וְלַשּׁוֹאֵל וְלַנּוֹשֵׂא שָׂכָר וְהַשּׂוֹכֵר נִכְנְסוּ תַחַת הַבְּעָלִים. מוּעָד מְשַׁלֵּם נֶזֶק שָׁלֵם וְתָם מְשַׁלֵם חֲצִי נֶזֶק. קְשָׁרוֹ בְעָלָיו בַּמּוֹסֵירָה וְנָעַל בְּפָנָיו כָּרָאוּי וְיָצָא וְהִזִּיק אֶחָד תָּם וְאֶחָד מוּעָד חַיָיב. רִבִּי יְהוּדָה אוֹמֵר תָּם חַיָיב וּמוּעָד פָּטוּר שֶׁנֶּאֱמַר וְלֹא יִשְׁמְרֶנּוּ בְּעָלָיו וְשָׁמוּר הוּא זֶה. רִבִּי אֱלִיעֶזֶר אוֹמֵר אֵין לוֹ שְׁמִירָה אֶלָּא סַכִּין.

MISHNAH: If it was handed over to an unpaid trustee, or a borrower, or a paid trustee, or a lessee, they entered instead of the owner; a notorious animal pays full damages, a tame one half damages. If he tied it down with a rope and locked it in as he should, if then it broke out and caused damage he is liable whether tame or notorious. Rebbi Jehudah says, for the tame he is liable, for the notorious he is not liable since it was said: “if its owner would not guard it,” but it was guarded. Rebbi Eliezer says, this one can be guarded only by the knife.

הלכה: מְסָרוֹ לְשׁוֹמֵר חִנָּם כול׳. אָמַר רִבִּי לָעְזָר. דִּבְרֵי רִבִּי מֵאִיר. שְׁמִירַת נְזָקִין כִּשְׁמִירַת שׁוֹמֵר חִנָּם. דִּבְרֵי רִבִּי יוּדָן. שְׁמִירַת נְזָקִין כְּשׁוֹמֵר שָׂכָר. אָמַר רִבִּי לָעְזָר. דִּבְרֵי רִבִּי מֵאִיר. מָסַר שׁוֹר לְשׁוֹמֵר חִנָּם. יָצָא וְהִזִּיק פָּטוּר. יָצָא וְנִטְרַף פָּטוּר. לְשׁוֹמֵר שָׂכָר. יָצָא וְהִזִּיק חַיָיב. יָצָא וְנִטְרַף פָּטוּר. אָמַר רִבִּי לָעְזָר. דִּבְרֵי רִבִּי יוּדָן. מָסַר שׁוֹר מוּעָד לְשׁוֹמֵר חִנָּם. יָצָא וְהִזִּיק חַיָיב. יָצָא וְנִטְרַף פָּטוּר. לְשׁוֹמֵר שָׂכָר. יָצָא וְהִזִּיק חַיָיב. נִטְרַף חַיָיב. אָמַר רִבִּי לָעְזָר. וַהֲלֹא שָׁמוּר הוּא וְהַתּוֹרָה חִיַּיבְתּוֹ. אָמַר רִבִּי לָעְזָר. כָּל שְׁמִירָה שֶׁאָמְרָה תוֹרָה אֲפִילוּ הִקִּיפוֹ חוֹמַת בַּרְזֶל אֵין מְשַׁעֲרִין אוֹתוֹ אֶלָּא בְגוּפוֹ. לְפִיכַךְ רוֹאִין אוֹתוֹ אִם רָאוּי לִשְׁמִירָה פָּטוּר וְאִם לָאו חַיָיב.

HALAKHAH: “If it was handed over to an unpaid trustee,” etc. Rebbi Eleazar said, the words of Rebbi Meïr that watching for damages is on the level of an unpaid trustee; Rebbi Jehuda said that watching for damages is on the level of a paid trustee. Rebbi Eleazar said, the words of Rebbi Meïr: If one handed over a bull to an unpaid trustee, if it went off and did damage, he is not liable; if it went out and became torn, he is not liable. To a paid trustee, if it went off and did damage, he is liable; if it went out and became torn, he is not liable. Rebbi Eleazar said, the words of Rebbi Jehudah: If one handed over a notorious bull to an unpaid trustee, if it went off and did damage, he is liable; if it went out and became torn, he is not liable. To a paid trustee, if it went off and did damage, he is liable; if it went out and became torn, he is liable. Rebbi Eleazar said, was it not watched? But the Torah declared him liable. Rebbi Eleazar said, for every guarding required by the Torah, even if it was done by enclosing in an iron wall, one only qualifies by personal presence. Therefore one determines whether he is qualified for watching; then he is not liable, otherwise he is liable.