Deuteronomy 23:13-15

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

15Thou shalt not deliver to his master the servant who hath escaped from his master to thee: