Most Jews are familiar with the mikveh (Jewish ritual bath) even if they have never immersed in one. The mikveh is used for conversions, for purification before the high holidays and for dedicating one’s new kitchen utensils. But it is probably most prominently associated with fulfillment of the laws of niddah. It is these so-called “laws of family purity” that compel married Jewish women all over the world to immerse in the mikveh after the completion of their menstrual cycles each month so they can resume marital relations.
It is apparent that Jews have regularly used mikvehs for millennia. Archaeologists have uncovered hundreds of ancient mikvehs all over Judea. The Mishnah, the foundational Jewish law code completed in the early third century CE, dedicates an entire tractate to their construction and use.
But it wasn’t always so. The earliest mikvehs date to the Hasmonean period, about 140 BCE. Before that, we don’t find any mikvehs at all. Why?
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We do not know for certain why Judaism so emphatically adopted the mikveh. Perhaps it was a response to wider societal and technological innovations. In this period, for instance, Romans bathed regularly in bathhouses. It is possible that Jews adapted that custom into their religious framework. The Torah itself, written in an earlier era, does not envision the building of structures for immersion in water.
So what does the Torah mean by “washing with water” for purification? It seems to have in mind a person simply pouring a jug of water over their head and body. On the rarer occasions that the Torah speaks of washing in “flowing waters” (as in Leviticus 15:13, where the Torah describes purification for a man after a seminal emission), it likely imagines using water from a stream, not an institutional ritual bath.
Sometimes, no washing is required for purification at all; just waiting a set amount of time will do. Niddah is just such a case. When the Torah describes how a woman is purified after her period it simply says: “When a woman has a discharge, her discharge being blood from her body, she shall remain in her menstrual separation seven days” (Leviticus 15:19). In other words, no water is required at all — the impurity departs on its own after a week, by which point, she is presumably no longer bleeding.
So how did Judaism develop the notion that a mikveh is essential for rituals like purification after menstruation? The short answer is: the rabbis, who come up with several homiletical proofs from scripture that women do, in fact, need to wash in order to be purified. For example, Rabbi Akiva states (Shabbat 64b):
“What does ‘she who is in her menstrual infirmity’ (Leviticus 15:33) come to teach? She shall remain in her menstrual state until she immerses in water.”
This is far from a literal reading of that innocuous phrase and, in some respects, only highlights the Torah’s omission of any requirement for the woman to wash, let alone use a mikveh, for purification.
Ironically, in our times, women immersing after their cycles has become the sine qua non of mikveh use, even though in Torah times, no form of washing was required. I think we can glean two opposite messages from this paradox.
On one hand, immersion in a mikvah offers women an important Jewish ritual that was missing previously — a bodily mitzvah on par with circumcision, which is obviously reserved for males. Indeed, some medieval rabbis declared explicitly that these are parallel “blood” mitzvot. On the other hand, knowing that the requirement to immerse monthly in the mikveh was a later addition to Jewish practice gives women who are ambivalent about the experience an opening to rely on the Torah as it once was, or to create an alternate path for themselves.
