Continuing the theme of Rabbinic decrees about clothing that might be removed and carried on Shabbat, the Mishna on today’s daf lists accoutrements that should not be worn by men on Shabbat. The first example in the Mishna is a sandal ha-mesumar – a spiked sandal. The Gemara explains that there is a different reason for the restriction that prohibits wearing a sandal ha-mesumar –
Shmuel said: They were those who eluded the decrees of religious persecution, and after one of the wars they were hiding in a cave. And those hiding said: One who seeks to enter the cave may enter, but one who seeks to leave the cave may not leave. One leaving has no way to determine whether or not the enemy is lying in wait outside the cave. Therefore, leaving could reveal the presence of those hiding in the cave. It happened that the sandal of one of them was reversed, the front of the sandal was in the back, and his footprints appeared like the steps of one leaving the cave. They thought that one of them left and feared that their enemies saw him and were now coming upon them to attack. In their panic, they pushed one another and killed one another in greater numbers than their enemies had killed among them. To commemorate this disaster that resulted from a spiked sandal, they prohibited going out into the public domain with it.
Similar explanations are offered by other amora’im. Ultimately the Gemara explains that since this incident took place on Shabbat, they issued the decree prohibiting the spiked sandal specifically in parallel circumstances. This is not the only case of a decree issued due to an event that transpired. There are similar instances. The principle is that in the wake of an event that left a particularly traumatic impression, the Sages issued decrees and established ordinances so that no such event would recur. Even when it was unlikely that the event would transpire a second time, they commemorated the event by means of their decree, much the same as they decreed fast days to commemorate tragedies that befell the Jewish people.
In the Jerusalem Talmud, additional reasons are cited for the decree prohibiting spiked sandals. Some explain that pregnant women would see the sandal, become frightened, and miscarry because it spurred memories of war. Others explain that they would be frightened by the noise of the spikes on the ground and miscarry. Therefore, the Sages issued a decree prohibiting wearing sandals of that kind.