Halakhah zu Schemot 30:20

That is that He commanded the priests to wash their hands and their feet any time they needed to enter the [Temple] chamber and do the service. And this is the sanctification of the hands and the feet. And this is His, may He be exalted, saying, "And let Aharon and his sons wash their hands and feet [from it]. When they enter the Tent of Meeting" (Exodus 30:19-20) And one who transgresses this positive commandment is liable for death at the hands of the Heavens - meaning to say that a priest that serves in the Temple without sanctification of the hands and feet is liable for death at the hands of the Heavens. And that is His, may His name be blessed, saying, "they shall wash with water, that they may not die" (Exodus 30:20). And the regulations of this commandment have already been completely explained in the second chapter of Zevachim. (See Parashat Ki Tissa; Mishneh Torah, The Chosen Temple 8.)