4,010. Washing From the Kiyor

Hilchos Bias HaMikdash 5:9

Let’s say that a kohein sanctifies his hands and his feet in order to remove the ashes from the altar. Even though he does so before sunrise, he need not sanctify them again after daybreak because he sanctified them at the start of the daily service.

Hilchos Bias HaMikdash 5:10

It is a mitzvah for kohanim to sanctify their hands and feet from the basin (called the kiyor in Hebrew) If one sanctified his hands and feet from a service vessel, they are duly sanctified, but this is not the case with a secular vessel. If a kohein sanctified his hands and feet with a service vessel outside the Temple, or if he used a secular vessel inside the Temple, the service that he performs is service is invalid. One may not sanctify his hands and feet by inserting them into the kiyor or a service vessel; rather, he uses water taken from them, as per Exodus 30:19: “Aaron and his sons will wash from it.” The Torah specifies “from it,” not “in it.” If a kohein sanctified his hands and feet inside a vessel, he does not profane the service that he performs.