Exodus 30:17-21

Then the LORD said to Moses, “Make a bronze basin, with its bronze stand, for washing. Place it between the tent of meeting and the altar, and put water in it. Aaron and his sons are to wash their hands and feet with water from it. Whenever they enter the tent of meeting, they shall wash with water so that they will not die. Also, when they approach the altar to minister by presenting a food offering to the LORD, they shall wash their hands and feet so that they will not die. This is to be a lasting ordinance for Aaron and his descendants for the generations to come.”