Numbers 19:10-13

10 The man who gathers up the ashes of the heifer must also wash his clothes, and he too will be unclean till evening. This will be a lasting ordinance both for the Israelites and for the foreigners residing among them.
11 “Whoever touches a human corpse will be unclean for seven days.
12 They must purify themselves with the water on the third day and on the seventh day; then they will be clean. But if they do not purify themselves on the third and seventh days, they will not be clean.
13 If they fail to purify themselves after touching a human corpse, they defile the LORD’s tabernacle. They must be cut off from Israel. Because the water of cleansing has not been sprinkled on them, they are unclean; their uncleanness remains on them.