Numbers 19:10-12

10The man who picks up the ashes must also wash his clothes. He will not be clean until evening. This rule is for the Israelites and for all the people who are living with them.

11Any person who touches a dead body will not be clean for seven days.

12He must use the water to wash himself on the third day and on the seventh day. Then he will be clean. If he does not wash himself on the third day and on the seventh day, he will not be clean.