Exodus 30:19-21

30:19 and Aaron and his sons must wash their hands and their feet from it. 30:20 When they enter the tent of meeting, they must wash with water so that they do not die. Also, when they approach the altar to minister by burning incense as an offering made by fire to the Lord, 30:21 they must wash their hands and their feet so that they do not die. And this will be a perpetual ordinance for them and for their descendants throughout their generations.”