Deuteronomy 23:12-14

12“You shall also have a place allocated outside the camp, so that you may go out there to relieve yourself, 13and you shall have a 1spade among your tools, and it shall be when you sit down outside, you shall dig with it and shall turn and cover up your excrement. 14Since 2the Lord your God walks in the midst of your camp to save you and to 3defeat your enemies before you, your camp must be 4holy; so He must not see 5anything indecent among you 6or He will turn away from you.