Matan and I are learning the end of the second chapter of Hagigah, about the laws of purity and impurity. Commentators explain that these laws are included in tractate Hagigah—which is about the commandment to bring sacrifices to the Temple on the pilgrimage festivals—because the entire nation had to be pure in order to enter the Temple. Throughout the rest of the year, not everyone was careful about the purity laws, even during Temple times. Broadly speaking, the Jewish people could be divided into two categories – Amei Haaretz, who were not strict in their observance of the purity laws, and the Pharisees (Perushim), who were.

Matan understands these categories immediately. “It reminds me of Corona,” he says, referring to the Covid-19 pandemic. “During Corona, some people were really strict about masks, and some people weren’t. But on airplanes, everyone had to observe the mask rules.” I think about his analogy. “So airplane trips are like the pilgrimage festivals, when everyone was extra-careful,” I add. “Which makes sense, since an airplane trip is a kind of pilgrimage.”

But presumably, the analogy goes only so far, because the laws of purity had nothing to do with masking. The Mishnah (2:5) teaches that there were different levels of purification that an individual had to engage in, depending on what he or she wanted to eat. If a person wished to eat ordinary bread, he would simply have to wash his hands ritually, as many do today. Such ritual handwashing would also suffice to enable that person to eat from tithed produce. However, if she wanted to eat sacrificial meat—since some of the sacrifices could be consumed in part by those who brought them—she would have to immerse her entire body in the ritual bath. “It reminds me of the Corona rules we had to follow last year,” Matan explains, extending the analogy further. “If you wanted to go to school, you had to take a Corona test twice a week. But if you wanted to go to a museum or to the zoo, you had to show your Green Pass with your vaccinations. And if you wanted to get on an airplane, you needed a test within twenty-four hours. Depending on what you wanted to be able to do, there were different levels of requirements.”

In the final Mishnah of the chapter (2:7), we learn that there was a hierarchy among individuals in terms of how strictly they observed the purity laws. In addition to the Pharisees, there were those who were even more stringent. The priests, for instance, kept stricter standards, because they ate from the tithed produce designated specifically for them. And those who ate from sacrificial meat had to be on an even higher level of purity. Finally, those on the highest level were the priests who dealt with the mei hatat – the waters of purification which contained the ashes of the red heifer and were used to purify anyone who had come into contact with the dead. The Mishnah explains that when a person who kept a higher standard of purity sat, leaned, or lay upon the garment of anyone who kept a lower standard of purity, he or she would become impure. For instance, if the priest who ate from the priestly tithe touched the garment of a Pharisee, the priest would become impure. “So the Pharisees were vaccinated, but maybe only once. The priests had to get the first booster as well, and the people who ate sacrifices got two boosters. And maybe the priests who came in contact with the dead were like those people who already had Corona and were completely immune.” Matan has it all figured out. The Mishnah’s ranking of degrees of purity indicates that it was important to keep track not just of one’s own degree of purity, but also of the garments and other items with which one came into contact. “Sounds like you really need an app for that,” Matan muses. “It would be hard to keep track of how pure you are, and what you touched. But an app could automatically measure your purity level depending on whether you washed your hands or went to the Mikveh or touched something impure. Especially if the app used GPS to track your location.”

I don’t exactly understand how GPS works, but I like the idea of a purity app. “I think I’m going to make one when the Temple is rebuilt,” Matan tells me. He explains that if you’re just an Am Haaretz, then you can get the regular membership, which would just tell you if you need to wash your hands or not. But if you’re a priest, then you can get the premium membership. “Like Spotify Premium,” he tells me. “It will tell you when you have to go to the Mikvah, and what you’re allowed to eat and touch at all times.”

I’m struck that Matan said he’s going to make his app “when” and not “if” the Temple is rebuilt. Though most of us hope never to have to return to the Covid protocols, there are Jews who very much hope and dream of a time when the Temple will be rebuilt. Matan’s use of “when” reminds me of the rabbis, who always took into account—when ruling in matters of halachah—that at any moment the Temple might be rebuilt, and we have to be prepared. The Torah teaches that when coming to the Temple on the pilgrimage festivals, you cannot appear before God “empty-handed” (Exodus 23:15), which the rabbis understood to mean that you need to arrive bearing sacrifices. Sounds like in the future, when the Temple is rebuilt, you’ll need to bring a smartphone too.