Numbers 31:23-25

American Standard Version

²³ everything that may abide the fire, ye shall make to go through the fire, and it shall be clean; nevertheless it shall be purified with the water for impurity: and all that abideth not the fire ye shall make to go through the water. ²⁴ And ye shall wash your clothes on the seventh day, and ye shall be clean; and afterward ye shall come into the camp.

²⁵ And Jehovah spake unto Moses, saying,