משנה: יָשַׁב אֶחָד עַל הַפֶּתַח וְלֹא מִילְאָהוּ וְיָשַׁב הַשֵּׁנִי וּמִילְאָהוּ הַשֵּׁנִי חַיָיב. יָשַׁב הָרִאשׁוֹן עַל הַפֶּתַח וּמִילְאָהוּ וּבָא הַשֵּׁנִי וְיָשַׁב לוֹ בְצִידּוֹ אַף עַל פִּי שֶׁעָמַד הָרִאשׁוֹן וְהָלַךְ לוֹ הָרִאשׁוֹן חַיָיב וְהַשֵּׁנִי פָּטוּר. לְמַה זֶּה דוֹמֶה. לְנוֹעֵל אֵֶת בֵּיתוֹ לְשׁוֹמְרוֹ וְנִמְצָא צְבִי שָׁמוּר בְּתוֹכוֹ:
MISHNAH: If one sat in the door opening but did not fill it and a second person came and filled it, the second is liable. If the first one sat in the door and filled it when the second came and sat next to him, even though the first one got up and left, the first is liable and the second not liable. To what can this be compared? To one who locks his house in order to watch it and it turns out that a deer is kept inside.