Reference

Leviticus 13:50

And the priest shall look upon the plague, and shut up it that hath the plague seven days:
48

Whether it be in the warp, or woof; of linen, or of woollen; whether in a skin, or in any thing made of skin;

49

And if the plague be greenish or reddish in the garment, or in the skin, either in the warp, or in the woof, or in any thing of skin; it is a plague of leprosy, and shall be shewed unto the priest:

50

And the priest shall look upon the plague, and shut up it that hath the plague seven days:

51

And he shall look on the plague on the seventh day: if the plague be spread in the garment, either in the warp, or in the woof, or in a skin, or in any work that is made of skin; the plague is a fretting leprosy; it is unclean.

52

He shall therefore burn that garment, whether warp or woof, in woollen or in linen, or any thing of skin, wherein the plague is: for it is a fretting leprosy; it shall be burnt in the fire.

Counter-Arguments

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

Pre-Law Clean/Unclean Distinction

This verse is found within the book of Leviticus, which details the Mosaic Law given at Sinai, and therefore describes a distinction *within* the Law, not one that predates it.

Symbolic / Spiritual Interpretation

The verse describes a literal physical inspection of a "plague" and a physical act of "shutting up" for a set number of days, with no language suggesting a symbolic or spiritual meaning for these actions or the "plague" itself.