As we learned on yesterday’s daf there was a daily requirement for the kohanim to begin their day of Temple service with ritual washing of the hands and feet every morning. According to the Mishna (15b) a sacrifice brought by a kohen who had not prepared himself appropriately by washing his hands and his feet, would be invalid. The kohanim were required to place their right hand over their right foot and their left hand over their left foot and wash them from the kiyor, the water basin in the Temple. During the Second Temple, twelve faucets were added to the kiyor in order to allow many kohanim to prepare themselves for service at the same time.
The Gemara on today’s daf asks whether it would suffice if a kohen bathed his hands and feet in the basin of the kiyor, rather than using the water from the faucets. While the passage commanding the kohanim to wash says that Aharon and his sons should wash their hands and feet mimenu – from it, from the kiyor (see 30:19) – perhaps placing hands and feet into the kiyor would accomplish the same thing.
Although it is clear that the word mimenu appears to be unnecessary and is therefore being used by the Torah to teach something, it is not clear that the conclusion must be that it limits the possibility of bathing hands and feet in the kiyor. It is possible to suggest that it means that the water used to wash up in the Temple must come from the kiyor and not from some other source. Furthermore given that purifying a person by means of a mikveh – a ritual bath – can only be done by immersion, and not by pouring from it, it is possible to suggest that mimenu comes to teach that it is sufficient to wash hands and feet from it, and it is not necessary to bathe them in the kiyor.
The Gemara does not reach a clear conclusion regarding this question, and the Rambam rules that kohanim should not bathe their hands and feet in the kiyor, although if a kohen did so, his sacrifice would be ruled valid (see Kesef Mishne, Rambam Hilkhot Biat HaMikdash 5:11).