Deuteronomy 23:11-13

New Revised Standard Version, Anglicised

¹¹ When evening comes, he shall wash himself with water, and when the sun has set, he may come back into the camp.

¹² You shall have a designated area outside the camp to which you shall go. ¹³ With your utensils you shall have a trowel; when you relieve yourself outside, you shall dig a hole with it and then cover up your excrement.