Deuteronomy 23:12-14

12“You must have a designated area outside the camp where you can go to relieve yourself.

13Each of you must have a spade as part of your equipment. Whenever you relieve yourself, dig a hole with the spade and cover the excrement.

14The camp must be holy, for the Lord your God moves around in your camp to protect you and to defeat your enemies. He must not see any shameful thing among you, or he will turn away from you.