This verse is part of the instructions in Leviticus 14 for dealing with a potentially infectious disease in a house. Here's a breakdown of what it means:

"then the priest shall go out of the house to the door of the house": The priest, acting as a religious official and an authority on ritual purity and disease control, has already examined the house and found what he suspects is a contaminating mold or mildew. He leaves the house.
"and shut up the house seven days": The priest orders the house to be sealed off or quarantined for a period of seven days. This is to prevent any potential spread of the infection and to allow time for further observation and assessment.

In essence, the verse describes the action of quarantining a house suspected of having a contagious issue. The purpose of the quarantine is to: the quarantine served as a period for observation and diagnosis. During this time, the priest would reassess the house to determine if the problem persisted or worsened, which would inform further actions

Symbolic Meanings and Interpretations (Beyond the Literal)

While the literal meaning deals with physical disease, some interpretations also find symbolic or spiritual meaning in these passages:

Sin and Separation: Some see the disease as a metaphor for sin, and the quarantine as a symbol of separation from God and the community due to sin.
Purification: The process of dealing with the disease, including the quarantine and subsequent cleansing rituals, can be interpreted as a process of purification and restoration to wholeness.

It's important to note that these are just possible interpretations, and the primary meaning of the verse is related to dealing with a potential health hazard in ancient Israel.