Deuteronomy 23:10-13

10"If any man among you becomes unclean because of a nocturnal emission, then he shall go outside the camp. He shall not come inside the camp,

11but when evening comes, he shall bathe himself in water, and as the sun sets, he may come inside the camp.

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.