Exodus 30:17-21

And Jehovah spake unto Moses, saying, Thou shalt also make a laver of brass, and the base thereof of brass, whereat to wash. And thou shalt put it between the tent of meeting and the altar, and thou shalt put water therein. And Aaron and his sons shall wash their hands and their feet thereat: when they go into the tent of meeting, they shall wash with water, that they die not; or when they come near to the altar to minister, to burn an offering made by fire unto Jehovah. So they shall wash their hands and their feet, that they die not: and it shall be a statute for ever to them, even to him and to his seed throughout their generations.