Deuteronomy 23:11-13

New International Version

¹¹ But as evening approaches he is to wash himself, and at sunset^(A) he may return to the camp.^(B)

¹² Designate a place outside the camp where you can go to relieve yourself. ¹³ As part of your equipment have something to dig with, and when you relieve yourself, dig a hole and cover up your excrement.