Parashas Metzora · Passuk 14:02
Chabad.org — English translation + Rashi
Torah Temima points to Menachos 19a (verified on the daf).
E-Daf.com — Tsurras Hadaf (size=3)
HebrewBooks / Shas PDF of the daf
English: “This shall be” — the four species used for the metzora hinder one another, for the verse says “this shall be the Toras of the metzora,” which is treated as if the word “chukah” were written.
Gezeiras ha-kasuv (chukah language)
Chazal teach that the four species of the metzora’s bird-rite (cedar wood, hyssop, crimson wool, and birds) are essential and mutually required; omission of any one invalidates the entire procedure.