On yesterday’s daf we learned of the incident where Rabbi Shimon criticized the Roman government and was condemned to death. The Gemara relates that Rabbi Shimon and his son hid in a cave for twelve years and survived miraculously on carob and water. The Gemara on today’s daf relates that when Rabbi Shimon finally was able to leave the cave he decided to perform an act of kindness for the community as a celebration of the miracle that saved him. The Gemara relates:
He (Rabbi Shimon) said: Is there something that needs repair?
They said to him: There is a place where there is uncertainty with regard to ritual impurity and the priests are troubled by being forced to circumvent it, as it is prohibited for them to become ritually impure from contact with a corpse. There was suspicion, but no certainty, that a corpse was buried there. Therefore, they were unable to definitively determine its status.
Rabbi Shimon said: Is there a person who knows that there was a presumption of ritual purity here? Is there anyone who remembers a time when this place was not considered ritually impure, or that at least part of it was considered to be ritually pure?
An Elder said to him: Here ben Zakkai planted and cut the teruma of lupines. In this marketplace
Rabbi Yohanan ben Zakkai, who himself was a priest, once planted lupines that were given to him as teruma. On that basis, the conclusion can be drawn that it was definitely ritually pure.
Rabbi Shimon, did so and took steps to improve the city and examined the ground. Everywhere that the ground was hard, he pronounced it ritually pure as there was certainly no corpse there, and every place that the ground was soft, he marked it indicating that perhaps a corpse was buried there. In that way, he purified the marketplace so that even priests could walk through it.
In the Jerusalem Talmud (Shevi’it 9:1) it is explained that Rabbi Shimon bar Yoḥai accomplished this miraculously. Everywhere that a corpse was buried, it would rise up from the earth. Although the Samaritans attempted to sabotage his effort, they were unsuccessful. Here, it is explained that Rabbi Shimon bar Yoḥai purified the ground by examining the texture of the soil to see whether or not the soil had been overturned at some point in the past.