Exodus 30:19

¹⁷  And the LORD spake unto Moses, saying,

¹⁸  Thou shalt also make a laver of brass, and his foot also of brass, to wash withal: and thou shalt put it between the tabernacle of the congregation and the altar, and thou shalt put water therein.

¹⁹  For Aaron and his sons shall wash their hands and their feet thereat:

²⁰  When they go into the tabernacle of the congregation, they shall wash with water, that they die not; or when they come near to the altar to minister, to burn offering made by fire unto the LORD:

²¹  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.