Although many of the laws of tum’ah ve-taharah – ritual purity and defilement – no longer apply to us, since the Temple is not standing, no sacrifices are brought and tithes are no longer eaten, even today kohanim must take care to avoid cemeteries and places where bodies may be buried. Our Mishna introduces two types of tum’ah:
- tum’ah yedu’ah– “known tum’ah,” and
- tum’at ha-tehom – “tum’ah that is deeply buried.”
According to the Mishna, these two situations are treated differently. If someone enters a body of water, intending to purify himself, and a dead body is found floating in the water (i.e. tum’ah yedu’ah), we assume that he came into contact with it (even though he was probably paying attention to the circumstances in the mikveh) and that he will be declared tameh. If, however, the dead body was hidden (and discovered later, i.e. tum’at ha-tehom), although we cannot say that a tameh person who entered that body of water will become purified, nevertheless, someone who entered the water in a state of ritual purity (simply for a swim or to cool off) will not be seen as having come into contact with the body and will be deemed tahor. The Mishna’s explanation for this is she-raglayim la-davar – that given the doubt that exists in this situation, it is reasonable to allow people to remain in their status quo.
The Gemara brings suggestions for a source for these halakhot. Rabbi Elazar brings the passage in Bamidbar (6:9) that appears to emphasize the need for the person to be aware that he was in close proximity to the dead man; Resh Lakish suggests the pasuk (see Bamidbar 9:10) that uses the term derekh – a path – implying that the dead should be clearly seen, like a path or road is clearly seen. Nevertheless, the Gemara concludes tum’at ha-tehom gemara gemiri lah – the rules of tum’at ha-tehom – are oral traditions that cannot be derived from a clear biblical source.