Numbers 31:22

²⁰And ye shall purify every garment and every leathern utensil, and all furniture of goat skin, and every wooden vessel.

²¹And Eleazar the priest said to the men of the host that came from the battle array, This is the ordinance of the law which the Lord has commanded Moses.

— Numbers 31:22 —

²³everything that shall pass through the fire shall so be clean, nevertheless it shall be purified with the water of sanctification; and whatsoever will not pass through the fire shall pass through water.

²⁴And on the seventh day ye shall wash your garments, and be clean; and afterward ye shall come into the camp.