Leviticus 14:37
And he shall look on the plague, and, behold, if the plague be in the walls of the house with hollow strakes, greenish or reddish, which in sight are lower than the wall; And he shall look on the plague, and, behold, if the plague be in the walls of the house with hollow strakes, greenish or reddish, which in sight are lower than the wall;
God gave Moses directions for the inspection of houses, and this examination of the walls for the plague belongs to those directions. Those directions required order in matters connected with His service. They likewise required cleanliness in matters connected with His service.