Yoma 32

How do we know what we know?

There are certain things that “everybody” knows. If you go out with wet hair, you’re likely to catch a cold. An apple a day keeps the doctor away. Life isn’t fair. And while some of these statements are scientifically grounded (doctors are unlikely to come near you if you throw fruit at them!), others are outright false (so there’s no need to invest in a hairdryer to prevent the common cold). But how do we know what we know? When “everybody” knows something, where does that knowledge come from? Today’s daf explores this issue in depth. 

Rav Hisda said: We learned in a tradition — five immersions and ten sanctifications the high priest immerses and sanctifies on the day (of Yom Kippur). 

The idea that the high priest immerses his whole body five times and sanctifies his hands and feet ten times on Yom Kippur is then repeated several times over the course of today’s daf. It is stated not only by the Amora Rav Hisda (a rabbi of the later generations that followed the closing of the Mishnah) but also by the Tannas Rabbi Yehuda and Rabbi Yehuda HaNasi (who belonged to earlier generations before the Mishnah was closed). And throughout the course of the daf, even more rabbis pick up and run with the idea. But where does this tradition come from?

Rabbi Yehuda suggests: They are derived from the verse that states: And Aaron shall come into the Tent of Meeting and he shall remove the linen garments that he put on when he entered the sanctuary and leave them there. And he shall wash his flesh in water in a sacred place and put on his garments, and he shall go out and perform his own burnt-offering and the burnt-offering of the people. (Leviticus 16:23–24)

Rabbi Yehuda HaNasi offers another origin: They are derived from that which is stated: He shall be dressed in a sacred linen tunic, and with linen trousers next to his flesh, and he shall be girded with a linen belt, and he shall wear a linen mitre; they are sacred garments, and he shall wash his flesh in water and then put them on. (Leviticus 16:4)

Both Rabbi Yehuda and Rabbi Yehuda HaNasi assert that the high priest’s five immersions and ten sanctifications derive from a biblical verse which states that the high priest shall “wash his flesh” — though they point to different verses with that language. Both prooftexts suggest that the high priest must immerse himself before putting on the ritual clothing necessary for each part of the service, so their debate is really just about which verse is the true origin of the practice. Knowing the origin doesn’t change the rabbis’ conclusion that the high priest requires five immersions, but it is important to them nonetheless! These two teachings then spark a further rabbinic discussion of why each immersion requires two sanctifications (the answer comes in the form of more biblical verses).

In his explanation of Rav Hisda’s original statement, the medieval commentator Rashi states that this tradition of five immersions and ten sanctifications is a “halakhah le-moshe mi-sinai,” a piece of the Oral Torah transmitted directly by God to Moses at Sinai, with no explicit — or even implicit! — biblical origins. But today’s daf seems to offer a different approach. According to the rabbis of today’s daf, “everybody” knowing something is not adequate — we must know exactly how and why it is the case.

Read all of Yoma 32 on Sefaria.

This piece originally appeared in a My Jewish Learning Daf Yomi email newsletter sent on May 13th, 2021. If you are interested in receiving the newsletter, sign up here.

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