Deuteronomy 23:9-11

Young's Literal Translation

⁹ `When a camp goeth out against thine enemies, then thou hast kept from every evil thing.

¹⁰ `When there is in thee a man who is not clean, from an accident at night -- then he hath gone out unto the outside of the camp -- he doth not come in unto the midst of the camp --

¹¹ and it hath been, at the turning of the evening, he doth bathe with water, and at the going in of the sun he doth come in unto the midst of the camp.