Shemoth (Exodus) 30:17-21

And יהוה spoke to Mosheh, saying, “And you shall make a basin of bronze, with its stand also of bronze, for washing. And you shall put it between the Tent of Appointment and the slaughter-place, and shall put water in it. “And Aharon and his sons shall wash from it their hands and their feet. “When they go into the Tent of Appointment, or when they come near the slaughter-place to attend, to burn an offering made by fire to יהוה, they wash with water, lest they die. “And they shall wash their hands and their feet, lest they die. And it shall be a law forever to them, to him and his seed throughout their generations.”