Reference

Leviticus 13:23

But if the bright spot stay in his place, and spread not, it is a burning boil; and the priest shall pronounce him clean.
21

But if the priest look on it, and, behold, there be no white hairs therein, and if it be not lower than the skin, but be somewhat dark; then the priest shall shut him up seven days:

22

And if it spread much abroad in the skin, then the priest shall pronounce him unclean: it is a plague.

23

But if the bright spot stay in his place, and spread not, it is a burning boil; and the priest shall pronounce him clean.

24

Or if there be any flesh, in the skin whereof there is a hot burning, and the quick flesh that burneth have a white bright spot, somewhat reddish, or white;

25

Then the priest shall look upon it: and, behold, if the hair in the bright spot be turned white, and it be in sight deeper than the skin; it is a leprosy broken out of the burning: wherefore the priest shall pronounce him unclean: it is the plague of leprosy.

Counter-Arguments

The strongest case that this verse does not belong in this theme.

Symbolic / Spiritual Interpretation

The verse describes a physical skin condition and a ritualistic determination of physical cleanliness, with no explicit or implicit language suggesting a symbolic or spiritual meaning for "clean" or "unclean."

Pre-Law Clean/Unclean Distinction

This verse is from the book of Leviticus, which is part of the Mosaic Law given at Sinai, not a text predating it. Therefore, it describes the clean/unclean distinction *within* the context of the Law, not before it.