Exodus 30:17-21 (NKJV)
¹⁷  Then the LORD spoke to Moses, saying:
¹⁸  “You shall also make a laver of bronze, with its base also of bronze, for washing. You shall put it between the tabernacle of meeting and the altar. And you shall put water in it,
¹⁹  for Aaron and his sons shall wash their hands and their feet in water from it.
²⁰  When they go into the tabernacle of meeting, or when they come near the altar to minister, to burn an offering made by fire to the LORD, they shall wash with water, lest they die.
²¹  So they shall wash their hands and their feet, lest they die. And it shall be a statute forever to them–to him and his descendants throughout their generations.”