Is a door still a door if you can’t pass through it?
Eruvin 78 ponders this question. Here’s the background:
As we have learned, when several houses open to a central courtyard, the residents of that courtyard may join together by means of a shared meal, the eruv, which allows them all to carry things in the courtyard on Shabbat.
If two adjacent courtyards are separated by a wall, each courtyard requires its own eruv. However, if a door, lowered wall, window, or other passageway allows people to get through the wall, then the two courtyards may use one eruv for everyone.
We have also seen that Eruvin 78 discusses some rather generous definitions of doors which would allow the two courtyards to share one eruv. For instance, an overturned basin or ladder that helps you get over the wall can sometimes be a sufficient passageway for this purpose.
The Talmud poses a question. If the residents of the houses in the two courtyards use a tree as a makeshift ladder to help them get over the wall, would that allow them to combine?
The question is not whether this method of crossing the wall is a terrible idea; the Talmud assumes that climbing a tree is a reasonable way to get across a wall. But climbing a living, blossoming tree is a violation of the laws of Shabbat.
The rabbis consider both the possibility that the tree would be considered a valid door and the possibility that it would not. Some sages argue that if climbing a tree is forbidden on Shabbat, the tree can’t be used to facilitate an eruv that helps us observe Shabbat.
However, others present the following argument to accept the tree:
It is a valid door, but a lion crouches upon it.
If a lion were standing in front of a door, you would not be able to walk through it. But it would still be a door, albeit one with an external problem. In this case, the tree is an acceptable way (in their eyes, anyway) of getting over the wall. There just happens to be an external reason – the laws of Shabbat – that prevents it from being used at the moment. But that should not stop us from considering this tree to be a door for the purposes of the eruv.
This vivid image of Shabbat as a fierce lion that prevents passage is somewhat reminiscent of the Jewish legend of the river Sambatyon, which is said to rage and throw up stones all week, and then become calm on Shabbat. The legend states that this river may never be crossed. During the week you can’t cross it because it is too dangerous, and on Shabbat you can’t cross it because of the prohibition against travel. — an impediment to crossing as significant as the rapids and flying rocks.
Today’s image is of Shabbat as a crouching lion apt. For the rabbis, Shabbat is not just a day of rest and renewal, but a real and terrifying force to be reckoned with. It can prevent you from crossing a river just as effectively as raging rapids and rocks. And it can prevent you from passing through just as much as a roaring lion on the doorstep.