Then the priest shall come and look,.... On the seventh day of the second week; though, according to Maimonides o, this was at the end of the third seven day, or on the nineteenth day from his first inspection into it; the seventh day being reckoned for the last of the first week, and the first of the second, and so on:
and, behold, [if] the plague be spread in the house; after all the above precaution is taken;
it [is] a fretting leprosy in the house; like that in the garment,
it [is] unclean; and so not to be inhabited.
o Hilchot Tumaat Tzarat, c. 15. sect. 1, 2.