Numbers 31:23-25

Amplified Bible, Classic Edition

²³ Everything that can stand fire, you shall make go through fire, and it shall be clean. Nevertheless it shall also be purified with the water of impurity; and all that cannot stand fire [such as fabrics] you shall pass through water.

²⁴ And you shall wash your clothes on the seventh day and you shall be clean; then you shall come into the camp.

²⁵ And the Lord said to Moses,