Numbers 31:19-20

King James Version

¹⁹ 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.

²⁰ And purify all your raiment, and all that is made of skins, and all work of goats' hair, and all things made of wood.