'Need' in the Bible

it is a chronic disease on the skin of his body, and the priest must pronounce him unclean. He need not quarantine him, for he is unclean.

the priest is to examine the person. If the scaly outbreak has spread on the skin, the priest does not need to look for yellow hair; the person is unclean.

The priest shall then command that they empty the house before the priest goes in to look at the mark, so that everything in the house need not become unclean; and afterward the priest shall go in to look at the house.