Deuteronomy 23:13-15

13There is to be a place at hand for you outside the camp, and you are to go there outside.

14You are to have a shovel for yourself among your weapons. Now when you sit down outside, you are to dig with it and turn and cover up what comes out of you.

15For Adonai your God walks in the midst of your camp, to rescue you and to give your enemies over to you. Therefore your camp must be holy, so that He does not see anything indecent among you and turn away from you.