לה) וְכִי יִגֹּף שׁוֹר אִישׁ אֶת שׁוֹר רֵעֵהוּ וָמֵת וּמָכְרוּ אֶת הַשּׁוֹר הַחַי וְחָצוּ אֶת כַּסְפּוֹ וְגַם אֶת הַמֵּת יֶחֱצוּן
לו) אוֹ נוֹדַע כִּי שׁוֹר נַגָּח הוּא מִתְּמוֹל שִׁלְשֹׁם וְלֹא יִשְׁמְרֶנּוּ בְּעָלָיו שַׁלֵּם יְשַׁלֵּם שׁוֹר תַּחַת הַשּׁוֹר וְהַמֵּת יִהְיֶה לּוֹ: ס
35 And if one man’s ox hurt another’s, so that it dieth; then they shall sell the live ox, and divide the price of it; and the dead also they shall divide. 36 Or if it be known that the ox was wont to gore in time past, and its owner hath not kept it in; he shall surely pay ox for ox, and the dead beast shall be his own.
Question: When a normal ox gores another ox, the owner is obligated to pay up to half the damage it caused. Yet he need not pay more than the value of his own ox that gored. Why is that?
Answer: When a person takes his ox into the public, he is responsible to watch it from causing normal ox-damage, like eating something. But cannot be fully expected to prevent unusual events such as the ox goring another ox or other violent acts. Therefore he only pays half damage. Even that may be too great a burden for him. What if his $100 ox gores a $1000 ox? He’ll go bankrupt! Since it’s not something he’s fully responsible for anyways, the Torah doesn’t want him to go into economic ruin. All that is certain that we can collect from is the very ox that gored. That is what he brought into the public domain and it his “guarantor” on any damage it may cause.
An example for modern readers would be if someone driving a cheap car gets into a collision with a much more expensive car. Its unlikely he will be able to pay for the damage, so it would be reasonable to have laws that limited his payments to the value of his own car.