Leviticus 14:52
And he shall cleanse the house with the blood of the bird, and with the running water, and with the living bird, and with the cedar wood, and with the hyssop, and with the scarlet: And he shall cleanse the house with the blood of the bird, and with the running water, and with the living bird, and with the cedar wood, and with the hyssop, and with the scarlet:
The command was given by God to Moses as part of His directions concerning houses and their cleansing. It belongs within that body of instruction dealing with how a house was to be cleansed. By prescribing the procedure in this way, God gave specific instructions for maintaining cleanliness in matters connected with His service.