We have already learned that the owner of an ox that has gored at least three times is held liable for full damages. It turns out that an ox can be forewarned for particular days of the week, as we learn in a mishnah:
The sages said before Rabbi Yehuda: What would be the halakhah if this ox is forewarned with regard to Shabbat but is not forewarned with regard to weekdays?
He said to them: For damage it causes on Shabbat its owner pays the full cost, and for damage it causes on weekdays he pays half.
And when is it rendered innocuous again?
It reverts to its innocuous status when its behavior reverts to normal (i.e., when it refrains from goring for three consecutive Shabbats).
In the case of an ox that gores only on Shabbat, the ruling of Rabbi Yehuda is that the owner is liable for full damages on Shabbat and half damages if it gores on weekdays. The ox is declared rehabilitated if it stops goring for three Shabbats in a row.
But does an ox really know when it is Shabbat as opposed to a weekday? How can an ox really be forewarned for Shabbat and not for other days of the week?
Perhaps, we might speculate, this is one of those rabbinic cases that is not so much realistic as it is theoretically interesting. Or perhaps, like people, animals benefit from rest on Shabbat and it changes their behavior on that day. Animals, too, are included in the commandment to observe Shabbat, as Exodus 20:10 states: “On the seventh day, a Sabbath unto Adonai your God, you shall not do any manner of work: you, your son, your daughter, your manservant, your maidservant, your cattle, or the stranger that is within your gates.”
While animals are entitled to rest on Shabbat, it’s possible that resting is not in the nature of animals. Therefore, an ox that is left to its own devices with no activity to occupy it on Shabbat might lash out simply because it’s bored and understimulated.
Tosafot, quoting the Jerusalem Talmud, has another suggestion for why an ox might be a habitual gorer only one day out of seven: On Shabbat, people wear beautiful clothing that differs from their normal attire. An animal might gore someone because it is either attracted to the finery or cannot recognize its neighbors around whom it typically behaves in a more docile manner because they’re dressed so differently.
Once we understand that an ox really might gore only on Shabbat, when its routine is so markedly different from the other six days of the week, this passage makes more sense. In order to keep an idle ox from lashing out, the animal’s owner must pay attention to its patterns and needs. Following the halakhah to ensure that an animal rests on Shabbat might not mean keeping it completely idle, and it might also require an owner to take extra steps to ensure that a change in routine doesn’t provoke the animal to lash out. Such care and consideration of one’s animal has benefits for both the ox and for the people who live in its orbit.