Numbers 31:19

Encamp outside the camp seven days . Whoever of you has killed any person and whoever has touched any slain , purify yourselves and your captives on the third day and on the seventh day .

“Anyone who has killed someone or touched someone who was killed must stay outside the camp seven days. On the third and seventh days you must purify yourselves and your captives.

And do ye abide without the camp seven days : whosoever hath killed any person, and whosoever hath touched any slain, purify both yourselves and your captives on the third day, and on the seventh day.