Exodus 30:19-21

19Aaron and his sons will wash their hands and feet there.

20They must wash with water whenever they go into the Tabernacle to appear before the Lord and when they approach the altar to burn up their special gifts to the Lord—or they will die!

21They must always wash their hands and feet, or they will die. This is a permanent law for Aaron and his descendants, to be observed from generation to generation.”