Numbers 19:12

12 He must make himself pure and clean with the special water. He must do it on the third day. He must also do it on the seventh day. Then he will be 'clean.' "But suppose he does not make himself pure and clean on the third and seventh days. Then he will not be 'clean.'

Numbers 19:12 In-Context

10 "The man who gathers up the ashes of the young cow must wash his clothes. He too will be 'unclean' until evening. That law is for the people of Israel. It is also for the outsiders who are living among them. The law will last for all time to come.
11 "Anyone who touches a dead person's body will be 'unclean' for seven days.
12 He must make himself pure and clean with the special water. He must do it on the third day. He must also do it on the seventh day. Then he will be 'clean.' "But suppose he does not make himself pure and clean on the third and seventh days. Then he will not be 'clean.'
13 Anyone who touches a dead person's body and does not make himself pure and clean makes my holy tent 'unclean.' He must be cut off from Israel. The special water has not been sprinkled on him. So he is 'unclean.' And he remains 'unclean.'
14 "Here is the law that applies when a person dies in a tent. Anyone who enters the tent will be 'unclean' for seven days. Anyone who is in the tent will also be 'unclean' for seven days.
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