Deuteronomy 23:13-14

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 2to cover up your excrement. 14Since 3the Lord your God walks in the midst of your camp to deliver you and to 4defeat your enemies before you, therefore your camp must be 5holy; and He must not see 6anything indecent among you 7or He will turn away from you.