Reference for Temurah 24:26

מה להלן עפר ע"ג המים אף כאן עפר על גבי המים

if he placed the dust before the water, it [the water] is ritually fit.<span class="x" onmousemove="('comment',' we thus see that according to the opinion of R. Simeon in connection with the waters of purification, if one puts first the ashes into the vessel before the water, the water is ritually fit.');">²¹</span>

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