זוב דמה,ואשה כי יזוב, “and if a woman have an issue of her blood, etc.” what is described here is what Solomon in Kohelet 10,18 alluded to when he said: בעצלתים ימך המקרה, “through slothfulness the ceiling sags, and through idleness of the hands, the house leaks.” The symbolism contained in this verse refers to the neglect by a woman in observing the laws of ritual purity, especially those laws involving menstruation. If the woman fails to examine herself before the onset of her menses this can have dire consequences, both for herself and the husband with whom she entertains marital relations. In the Talmud tractate Shabbat second chapter, death in childbirth by a woman is mentioned as one of these consequences. If she handled certain hallowed foods while in a state of ritual impurity, she made these foods unfit for consumption and conferred ritual impurity on the party handling them without even having eaten them. An interesting story on this subject is related in the Talmud, tractate, Niddah, folio 6. The famous Rabbi Gamliel had a servant woman working for him, who would regularly be required to seal caskets of wine [of a highly consecrated level, Ed.] and move them to another. After each single time she had moved them, she examined herself about whether her menses had begun, as otherwise the whole casket and its contents would have been unfit for further use. This servant maid found that after she had moved the last casket she had started her period. Upon telling this to her master, she was told that if she had not been in the habit of checking herself after each time she moved a casket, not only the last one but all of them would have become ritually contaminated. This is also why on folio 13 of the same tractate, we have a statement to the effect that anyone who makes a point of frequently checking herself out in this respect is especially praiseworthy.

ואחר תטהר, “and after that she is ritually clean.” Immersion of her whole body in forty measures of water in the ritual basin are what made her clean. Our sages in the Talmud tractate Eyruvin, folio 75 derive this from the words: אך במי נדה יתחטא, “but in the waters in which a menstruating woman bathes it will be cleansed.” [after waiting for the appropriate number of days without bleeding, Ed.] (Numbers 31,23). In verses 16-17 in our chapter, these steps to obtain ritual cleanliness are spelled out. Midrash Rabbah on Isaiah 8,6, describing the slow moving river Shiloah as moving לאט, points out that the numerical value of that word is 40; hence 40 saah of rainwater or well water is the minimum required for a ritual bath this has become the minimum amount stipulated by our sages as adequate for submersion.