The cleansing of contaminated houses is a biblical practice detailed in the Old Testament, specifically in the book of Leviticus. This practice is part of the broader Levitical laws concerning purity and cleanliness, which were given to the Israelites to maintain holiness and prevent the spread of disease and impurity within the community.

Biblical Reference:

The primary scriptural reference for the cleansing of contaminated houses is found in Leviticus 14:33-53. This passage outlines the procedures to be followed when a house is suspected of having a defiling mold or mildew, often referred to as "leprosy" of the house, though it is distinct from the leprosy affecting humans.

Procedure:

1. Inspection by the Priest: When a homeowner notices a suspicious mark on the walls of their house, they are to report it to the priest. The priest then inspects the house to determine if the contamination is indeed a defiling mold. Leviticus 14:35-36 states, "The owner of the house shall come and tell the priest, ‘Something like mildew has appeared in my house.’ The priest must order that the house be cleared before he goes in to examine the mildew, so that nothing in the house will be pronounced unclean."

2. Quarantine and Re-inspection: If the priest finds the mold to be potentially harmful, the house is to be closed up for seven days. After this period, the priest returns to inspect the house again. If the mold has spread, further action is required.

3. Removal of Contaminated Stones: Should the mold have spread, the contaminated stones are to be removed and discarded outside the city in an unclean place. The house is then scraped, and the plaster is replaced with new stones and mortar.

4. Second Quarantine: If the mold reappears after the stones have been replaced, the house is quarantined again. Persistent contamination results in the house being torn down, with all materials taken to an unclean place outside the city.

5. Cleansing Ritual: If the mold does not reappear, the house is declared clean. The priest performs a cleansing ritual involving two birds, cedar wood, scarlet yarn, and hyssop. One bird is sacrificed over fresh water, and the living bird, along with the cedar wood, scarlet yarn, and hyssop, is dipped in the blood of the sacrificed bird. The house is then sprinkled seven times with this mixture. Leviticus 14:51-52 describes this process: "He shall then take the cedar wood, the hyssop, the scarlet yarn, and the live bird, dip them into the blood of the slaughtered bird and the fresh water, and sprinkle the house seven times. And he shall cleanse the house with the blood of the bird, the fresh water, the live bird, the cedar wood, the hyssop, and the scarlet yarn."

6. Release of the Living Bird: The living bird is released into the open fields, symbolizing the removal of impurity and the restoration of the house to a state of cleanliness.

Theological Significance:

The cleansing of contaminated houses underscores the importance of holiness and purity in the life of the Israelites. It reflects God's concern for both the physical and spiritual well-being of His people. The detailed procedures emphasize the seriousness with which God views impurity and the lengths to which His people must go to maintain a holy environment.

Moreover, the ritual elements, such as the use of blood and the release of the living bird, foreshadow the ultimate cleansing and redemption found in Jesus Christ. The blood signifies atonement, while the release of the bird symbolizes freedom from sin and impurity. This practice, like many others in the Levitical law, points to the greater spiritual truths fulfilled in the New Testament through Christ's sacrifice.