On Monday afternoon, a group of approximately 500 set out from the Dung Gate of the Old City of Jerusalem, singing and dancing as they descended into the valley below Jerusalem with one goal in mind: to draw one small jug of water from the Shiloah Pool in order to reenact the Temple water ceremony.I am not a specialist in the Mishnah, so check anything I say about it with an expert. But I'm pretty sure that it is this ritual that is described in m. Sukkah 4.9.
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Sukkot (Tabernacles, Booths) is, of course, prescribed in the Bible (I have collected all the references here), but this particular Sukkot ritual is not mentioned there. We have no way of knowing whether it actually took place in Temple times, but that's what the Mishnah says.
UPDATE (11 October): Richard Bauckham e-mails: "It is often said that the account of Jesus at Sukkot in John reflects the two themes of Sukkot in the Mishna: water (7:37) and light (8:12)."
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