Numbers 31:19-20

New American Standard Bible

^19 (A)And as for you, camp outside the camp for seven days; whoever has killed a person and whoever has touched anyone killed, purify yourselves, you and your captives, on the third day and on the seventh day. ²⁰ And you shall purify for yourselves every garment, every article of leather, every work of goats’ hair, and every article of wood.”