Deuteronomy 23:13-14

13and thou shalt have a paddle among thy weapons; and it shall be, when thou sittest down abroad, thou shalt dig therewith, and shalt turn back and cover that which cometh from thee: 14for Jehovah thy God walketh in the midst of thy camp, to deliver thee, and to give up thine enemies before thee; therefore shall thy camp be holy, that he may not see an unclean thing in thee, and turn away from thee.