Deuteronomy 23:9-14 - Cleanliness Of The Camp
9 When you go out as an army against your enemies, guard yourselves against anything impure. 10 If there is someone among you who is impure because of some nocturnal emission, he must leave the camp; he may not reenter it immediately. 11 When evening arrives he must wash himself with water and then at sunset he may reenter the camp. 12 You are to have a place outside the camp to serve as a latrine. 13 You must have a spade among your other equipment and when you relieve yourself outside you must dig a hole with the spade and then turn and cover your excrement. 14 For the Lord your God walks about in the middle of your camp to deliver you and defeat your enemies for you. Therefore your camp should be holy, so that he does not see anything indecent among you and turn away from you.