Numbers 19:12

12 He must purify himself with [these ashes] on the third and seventh days; then he will be clean. But if he does not purify himself the third and seventh days, he will not be clean.

Numbers 19:12 In-Context

10 The one who collected the ashes of the heifer is to wash his clothes and be unclean until evening. For the people of Isra'el and for the foreigner staying with them this will be a permanent regulation.
11 "Anyone who touches a corpse, no matter whose dead body it is, will be unclean for seven days.
12 He must purify himself with [these ashes] on the third and seventh days; then he will be clean. But if he does not purify himself the third and seventh days, he will not be clean.
13 Anyone who touches a corpse, no matter whose dead body it is, and does not purify himself has defiled the tabernacle of ADONAI. That person will be cut off from Isra'el, because the water for purification was not sprinkled on him. He will be unclean; his uncleanness is still on him.
14 "This is the law: when a person dies in a tent, everyone who enters the tent and everything in the tent will be unclean for seven days.
Complete Jewish Bible Copyright 1998 by David H. Stern. Published by Jewish New Testament Publications, Inc. All rights reserved. Used by permission.