Midrash su Levitico 14:54

12) (Vayikra 13:59) ("This is the law of the plague-spot of leprosy, in a garment of wool or linen, or in the warp, or in the woof, or in any article of skin, to declare it clean or to declare it unclean.") "This is the plague-spot of leprosy, etc.": (Vayikra 14:54) ("This is the law for all plague-spots or leprosy and for a nethek (Vayikra 14:55) and for the leprosy of a garment and of a house.") They (plague-spot garments) are being likened to a house, viz., Just as a house is rendered unclean by the entry (of an unclean person), so it is rendered unclean by the entry of all (plague-spot garments). — But perhaps just as a house requires birds (for its cleansing, [viz. Vayikra 14:49]), so all (plague-spot garments) should require birds (for their cleansing)! It is, therefore, written "This" (i.e., only in this respect [that of "entry"] are they similar, and not in the other.) Rebbi says: It is written "This is the law for all plague-spots of leprosy and for a nethek and for the leprosy of a garment and of a house." Just as a house renders unclean by entry, so all are rendered unclean by entry. This tells me only of a garment. Whence do I derive all of them (i.e., warp and woof, etc.) for inclusion? From "This is the law of the plague-spot of leprosy … in the warp or in the woof, etc." Just as a garment renders unclean by entry, so all (i.e., warp and woof, etc.) render unclean by entry. — But perhaps just as a garment is rendered unclean by all that are tamei (e.g., sheratzim, semen, etc.), so all (warp and woof etc.) are rendered unclean by all that are tamei! It is, therefore, written "This" (and not the others).

16) (Vayikra 14:54) "This is the law, etc.": Whence is it derived that a Cohein who is expert in plague-spots (i.e., se'eth, sapachath, and bahereth), but not in nethakim; in nethakim, but not in karachoth; in karachoth, but not in shechin and michvah; in shechin and michvah, but not in garments; in garments, but not in houses — (Whence is it derived that) he should not examine plague-spots until he is expert in (all of) them and in their names? From (Vayikra 14:54-57) "This is the law for all plague-spots of leprosy and for a nethek and for the leprosy of a garment and of a house, and for a se'eth, and for a sapachath, and for a bahereth, to teach" (i.e., he should not teach others unless he is expert in all of them). (Vayikra 14:57) Rebbi says: "on the unclean day and on the clean day": We are hereby taught that he rules "unclean" in the daytime and he rules "clean" in the daytime. Chananiah b. Chachonai says: What is the intent of "to teach"? We are hereby taught that he does not examine plague-spots until his master teaches him.