Deuteronomy 23:12-14

12"You shall have a place outside the camp, and you shall go out to it.

13And you shall have a trowel with your tools, and when you sit down outside, you shall dig a hole with it and turn back and cover up your excrement.

14Because the Lord your God walks in the midst of your camp, to deliver you and to give up your enemies before you, therefore your camp must be holy, so that he may not see anything indecent among you and turn away from you.