On today’s daf, the Gemara pivots from priestly matters to a teaching about what to do when a person’s garment becomes stained with blood or fat. Because these two substances can carry ritual impurity, a person whose clothing is befouled with them is required to immerse the garment in a mikveh — unless the stains are part and parcel of the owner’s work.
Rava said: It is obvious to me that if there is blood on one’s garment, it interposes (between the water of immersion and the garment, and therefore the immersion is ineffective). But if he is a butcher, a bloodstain does not interpose. If there is fat on one’s garment, it interposes. But if he is a fat seller, such a stain does not interpose.
Before we interrogate Rava’s ruling, let’s take a moment to address the issue of interposition. When an impure garment is immersed in a ritual pool, in order for purification to be effective, nothing can come between the item and the water that surrounds it. Rava’s question here is whether stains that would typically invalidate purification can, in certain circumstances, be excluded from consideration as an interposition.
Rava first cites the general rule: If there is blood or fat on a garment it interposes between the mikveh water and the clothing, rendering the immersion ineffective — that is, the garment would still be ritually impure. Then he notes exceptions to the rule: work clothes. So if blood spots are found on a butcher’s apron or fat droplets on a fat seller’s garment, dunking it in the mikveh would purify it anyway. In the Mishneh Torah (Immersion Pools 3:6), Maimonides endorses this view. Blood on a butcher’s garment is not considered an intervening substance because the butcher does not object to its presence. The same goes for fat stains on the apron of a fat seller. Maimonides also expands the ruling, noting that “similar laws apply in all analogous situations.”
Next, Rava asks what the law would be if the situation is reversed and blood appears on a fat seller’s apron or fat stains a butcher’s garment.
The Gemara answers:
If he is a butcher, let me derive (that the stain interposes) due to the fat, and if he is a fat seller, let me derive (that the stain interposes) due to the blood.
In this case, stains that do not pertain to the specific work of the wearer would, in fact, block ritual immersion from being effective, since they are not typical to the garment.
What if both stains are present?
Is it that he is not particular with regard to one (stain), but he is particular with regard to two (stains)? Or, perhaps, he is not particular even with regard to two stains (as neither is unusual for him)? Let the question stand unresolved.
In this case, the Gemara has no easy answer. It is certainly possible that a butcher also works with fat and would get those stains on her apron, and likewise a fat seller might work with animals and get blood stains on his. Are one or the other stains less typical than the other? It’s impossible to say, so the rabbis decline to rule.
Today, even though we don’t immerse clothing in a ritual bath, those who use a mikveh for spiritual purposes still need to contend with the issue of interposition. For example, women who visit the mikveh are counseled to remove makeup, nail polish, bandages and the like before immersing so they are completely enveloped by the ritual waters. We’ll learn much more about that topic when we get to Tractate Niddah less than a year and a half from now.
Read all of Zevachim 98 on Sefaria.
This piece originally appeared in a My Jewish Learning Daf Yomi email newsletter sent on December 21, 2025. If you are interested in receiving the newsletter, sign up here.
