Deuteronomy 23:12-14

12Thou shalt have a place also outside the camp, where thou shalt go forth abroad: 13And thou shalt have a shovel among thy weapons; and it shall be, when thou wilt ease thyself abroad, thou shalt dig with it, and shalt turn back and cover that which cometh from thee:1 14For the LORD thy God walketh in the midst of thy camp, to deliver thee, and to give up thy enemies before thee; therefore shall thy camp be holy: that he may see no unclean thing in thee, and turn away from thee.2