Commento su Shabbat 13:6

צבי שנכנס – [a deer who enters] on its own into the house and someone locks [the door] before him, that is his “hunting.”

Introduction This mishnah is similar to 10:5 above, where we learned that if two people jointly perform a labor that could have been performed by one person, they are exempt. If they jointly perform a work that required two people, the sages say that both are liable and Rabbi Shimon exempts them both.

נעלו שנים פטורים - because two have done it (i.e., neither of them completed the act on his own).

If a deer enters a house and one person shuts [the door] before it, he is liable. By closing the door, she is liable, even though she didn’t actually cause the deer to come into the house.

לא יכול אחד לנעול – it is the manner to lock it in with two [people], each of them has [performed] a [forbidden] labor that without him [doing so], it would not have been accomplished.

If two shut it, they are exempt. If one could not shut it, and both shut it, they are liable. Rabbi Shimon exempts them. If two shut the door, both are exempt because they have both performed only half a labor. However, if the door was so large (or the people so small!) that they could only close it together, they are both liable. Rabbi Shimon exempts them, because he holds that two people can never be liable for one jointly performed labor.

ור"ש פוטר – but the Halakha is not according to Rabbi Shimon.